This problem seems to only affect Combat Arms when it is run through Steam. A temporary fix is to leave the error message up instead of closing it and bring the game client back up. This fixes the problem of the game minimizing every few minutes to show the error but unfortunately the messenger still does not work.
A fix for Windows Vista & 7 is to run steam as an administrator before attempting to launch Combat Arms.
- Go into your program files and look for the application steam.exe.
- Right click and press run as administrator
- Then press allow on the window that pops up.