Yep
i am also having that issue...
I have a Steam bought Version and a Retail Copy. and it is doing it in both.
I have turned the auto-updater off in steam for all my games I use trainers on but there doesn't appear to be a way to prevent all the tiny steam-client updates which can render the current trainer invalid.
It doesn't matter if you bought the game in disk form from a store all versions use Steam to install the game and this seems to be a growing trend. I think Steam is great except for all these client updates. The only way it appears to turn them off is to run in off-line mode but then any achievements you earn are not counted.
the actual steam client itself should have no impact at all on the reliability and functionality of a trainer, the trainer runs off the games .EXE which isn't part of steam whatsoever (unless it's made by Valve) it will be an external piece of software that simply uses Steam for purchase verification and launching. Some you can even launch directly from the game Dir without Steam even running - so your problem is most likely to do with patch version / trainer version incompatability.
Hope this is helpful?
Edit: Also, are you deffinately running the trainer in administrator mode (on vista+)? If so, are you also running steam in Administrator mode? This can sometimes alter the importance parameters when it launches games (since it's running in admin mode, it launches games in admin mode also)
[Edited by FireflyPoi, 9/5/2010 9:28:10 PM]
I hear what u r saying but why does CH have to sometimes come up with an emergency modified trainer when it concerns a game running off of steam?
I have heard many times, from the guys running CH, that a steam update rendered the current trainer invalid and need to come up with a new version.
new version uploaded. tested and working fine in skirmish.
thx PWizard, you guys at CH are the best.