Hi,
I'm new to the forum, so I hope this is a good place for a topis as such.

When I'm trying to play singleplayer mods error "Failed to contact game server" shows up. I can still play single player HL1 or multi with no problems. Currently, I have 2 mods, "TWHL Tower" and "Catharsis". First have its normal looking menu, but now I can't start the game (previously I was able to do that), situation with second is more complicated - when I first try to run the mod via "change game", HL crashes, and then on second attempt instead of normal letters there are only white rectangles and when trying to start the game, previously mentioned error shows up.
I think the problem started after I put in the HL folder mod called "Mission of Mercy", but I couldn't run it either, so maybe the problems started after putting there "TWHL T" folder, just for other mods first and then for itself? I don't know. Closing steam and opening it, as well as reinstall, don't fix this.

Additionally, sometimes when exiting mod, this message shows up:
"Debug assertion failed!
[directory of file]
File:dbgheap.c
Line:1132
Expression: _CrtIsValidHeapPointer(pUserData)
For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts."

...and I can choose to Abort, Retry (debugging of application) or Ignore, but neither of them do any difference. After that, another error shows up, this time saying almost the same things except for "Line:1190" and "Expression: _pLastBlock == pHead".
I'm using Steam version of HL1.

Does anyone have any suggestions?