Garry's mod keeps crashing after cca. 5 minutes of multiplayer

Hey,
my Gmod keeps crashing. I am playing DarkDM for five-ten minutes, then it crashes with my “favourite” windows message that hl2.exe encountered an error and needs to be closed.
Specs:
Graphics card: NVIDIA GT 220M (newest drivers)
CPU: Intel Core 2 Duo CPU @2,2GHZ each core
OS: Windows 7 Home Premium 64bit
Crash dump - http://dumps.garrysmod.com/?view=4151800676
Another crash dump - http://dumps.garrysmod.com/?view=1663386282
Thank you for help.
I start singleplayer game before each multiplayer one, as it crashes on sending client info when I dont.

According to https://support.steampowered.com/kb_article.php?ref=4168-TLZB-4976, I checked the DCOM service settings, it was already set up right. Not sure about the WMI thing, and I am not permitted (yes, I launched command line as Administrator) to add the Local Users group to Administrators.

Is your Windows in English, someone mentioned this:

“For the record - if you’re using a foreign language version of Windows, you’ll need to replace “Administrators” with the group name for your language. So for German, this will be ‘net localgroup Administratoren NetworkService /ADD’, for French ‘Administrateurs’, for Spanish ‘Administradores’ etc”

I know how to work with command line. But adding Local User to Administrators is a serious risk, and thus I am not permitted to do that.

Edit: Problem fixed, running Steam as administrator from now.
Lock request!