Dig deeper.
With all the crap that gets loaded onto PC's and latops, it's not so simple to just say "it ain't working" or even why. In my case, using Sony Vegas Pro 8.0c, I'm regetting that and backing down to 8.0b. I just did a wipe and re-install of my main computer this weekend, and so I know it's NOT the OS(plus, other people are saying the same thing).
Everybody seems to want to install something not essential. Why? Because they can, apparently. That's one of the problems with Windows, or really could be any OS for that matter. Say, for example, Nero, wants to put all this indexing and media sniffing crap on my machine, and I don't want it. Roxio has to load it's own bundle of unwanted crap. And since we're all going for performance, last thing I need is the latest Quicktime loading all sorts of gobs of goodies I don't even get a damn about.
I do agree that MyDMX should be run on an AC powered computer. No question about that. The dongle must be USB powered, so that means "we're draining the power faster". Hey, it could be worse, it could be like my M-Audio Firewire 410, which is firewire bus powered, and that can be quite the power pig! Adding more USB devices, bus-powered or otherwise, does lead to faster draining. Thank goodness you are on AC power AND in an "always on" mode.
Maybe it's your DJ software. Well, maybe not the DJ software itself, but perhaps something tied to it, that in and of itself is not a problem, but perhaps MyDMX doesn't like something. Are you using the 3D Visualizer with MyDMX when doing your DJ software? I can probably assume that you're not since it's not necessary at this point in time.
Are you running any MIDI hardware or controllers, even if USB devices?(say, a Korg Nano-something? I'm getting the NanoKontrol tomorrow) Perhaps MyDMX is getting confused by something. I don't know how DJ software works, but I could certainly see some sort of interface via USB or firewire to help do effects and battle things.
It is possible to be a hard drive sleep issue, that always screws things up.
Look into what you've got running. Ensure you are NOT using your wireless at the time. I find it really screws things up with ProTools, and I've had BETTER performance using Sonar Home 6 with it off, as well as improved performance and reliability with MyDMX by disabling it. Just, wireless consumes too much resources and is overall not super reliable anyways due to the nature of it. But, since I am using a MacBookPro, I typically boot to Mac to use ProTools, but even so, Wireless is still getting turned off.
I'm not without my share of problems from MyDMX, but I'm pretty much in a zone where I can live with it as I know what to do, or rather not do. Don't boot with the dongle plugged in. Have wireless disabled, then reboot(it often crashes the computer when I try to disable it after doing a few things. I boot up, disable, reboot, takes care of it). I had a 3-day event, and granted, I was only doing very simple scene changes and MyDMX didn't see a lot of heavy duty action. But, a typical event would run from 10AM to midnight(14 hours) and MyDMX ran without so much as a hiccup on that MacBook Pro, running XP Home and Boot Camp 2.1. All things considered, that is NOT MyDMX's ideal situation. Could be worse, I could be using the Parallels emulator software, but I just don't trust those ever.
Let me as this question: Are you SURE that MyDMX was NOT doing anything? My problems with MyDMX at an event was MyDMX was moving in super slow-mo(say, taking 3 minutes to do what normally would be a 2-second fade), and even then, I'm not sure if anything was being sent down the line. Due to the fact that the "show must go on", I simply switched to my DMX Operator and kept on chugging. But that was a one-off, and it was because I booted with the dongle plugged in. Next event a short while later, no grief from MyDMX.
Also, don't say your system specs won't cause the issue, 'cause, it CAN. Some Dells and Gateways had a history of stupidity on the USB and/or firewire, making them unsuitable for pro audio. This was NOT a software issue, it was poor hardware design.
Also, DON'T rule out that your machine is "Just for this and that", although let's face it, the fact that your machine is being used in a more or less application specific environment is a GOOD THING. My machines are typically purpose built: They are designed to do a few things SUPER good, and I don't give a crap if they do anything else. I have low end machines I can use for "office" type tasks, saving my horsepower for the upper end machines for the buttkicing tasks. My MacBook Pro was bought for 1 reason: ProTools. At the time, ProTools and the latest Mac OS X(10.5.2) was NOT compatible with ProTools, so I could use the laptop as a PC and keep on going until Digi had a fix. Since they fixed it, I still use it mainly as a PC, but for audio, it's Mac time.
But back to not ruling out your machine based on specs is foolish. Is this something YOU wiped CLEAN and then controlled ALL of the software getting loaded onto it? Any store-bought system is gonna be chock full of crap that in some cases CAN NOT be totally removed. While the hardware may be solid, the software can cause disasters. Of course, this requires a bit extra money for the OS license and the patience to get it done. But, I redid my main computer this weekend, and with breaks(including SLEEP, a birthday party, watching a DVD with the kids and a few other hours just frittered away), it was done in less than 24 hours, and that also INCLUDED having to download Service Pack 2(I had SP3 handy, something I will correct by keeping SP2 nearby). Hardware with crappy software is just plain crappy.
USB: Maybe you're ONTO something. I do recommend ALL users to have a POWERED USB hub whenever possible. Also, I would recommend a good name brand one that is designed for pro audio. These have less clocking and latency issues than regular ones. The cost is typically less than $10 more for these ones. I personally am trying to avoid carrying around a powered USB hub(or any hub) mainly because that's one more thing to forget or fail or cause grief, noise or give me issues with plugging it in come gig time, especially since I am always under the gun and pressed for time.
Also, not to cloud things further, but how long was your DMX run, and were you using DMX cabling? Also, it has come to my attention that MyDMX dongle doesn't really push the line that hard, but I've had no issues with it driving over 300 feet of cable. Even so, I've upgraded to an OptiBranch/4 for multiple reasons. Also, EddwardM brings up a good point about termination, which is something I've gone on about as well. These are all critical tools we all need in our pockets. I'm going a step further and going to build myself a DMX tester(just tests for presence of signal, not if there are PROBLEMS with it) and a phantom power tester. Gotta see if I can borrow the car and head to an electronics store this week! But, the point I am making is that it can cost under $7 to build these testers and terminators and as such, being so cheap, we have little excuse for NOT having these items as applicable to our situation. For example, I don't expect a DJ to need a phantom power tester, but if he has lights, he needs a DMX terminator and tester.