I got tired of hassling with this so I just moved my KillingFloor.ini to another folder, to let the game create a new one. After I had done that and changed all settings back to what I had previously I exited the game and compared the new .ini with the old one in Beyond Compare. The only differing entries I found were entries that didn't exist at all in the new one (everything else was just the same).
These are the ones that were in my old .ini but not in my current (working) one:
TimeBeforeReboot=5.000000
MaxScrollbackSize=128
PasswordPromptMenu=
ChatMenuClass=GUI2K4.UT2K4InGameChat
StatsPromptMenuClass=GUI2K4.UT2K4StatsPrompt
WaitingGameClassName=
ServerInfoMenu=GUI2K4.UT2K4ServerInfo
SteamLoginMenuClass=ROInterface.ROSteamLoginPage
GameConfig=(GameClass="KFMod.KFDMGameType",Prefix="KFDM",Acronym="KFDM",GameName="poundamonium",Mutators="UTV2004s.utvMutator",Options=)
GameConfig=(GameClass="XGame.xDeathMatch",Prefix=,Acronym=,GameName="new",Mutators=,Options=)
[IpDrv.UdpGamespyQuery]
MinNetVer=0
OldQueryPortNumber=7717
bRestartServerOnPortSwap=True
bDebugPortSwaps=True
[KFmod.KFConsole]
SMOriginX=0.010000
SMOriginY=0.300000
LetterKeys[0]=IK_Q
LetterKeys[1]=IK_W
LetterKeys[2]=IK_E
LetterKeys[3]=IK_R
LetterKeys[4]=IK_A
LetterKeys[5]=IK_S
LetterKeys[6]=IK_D
LetterKeys[7]=IK_F
LetterKeys[8]=IK_Z
LetterKeys[9]=IK_X
bSpeechMenuUseLetters=False
bSpeechMenuUseMouseWheel=True
PasswordPromptMenu=
ChatMenuClass=GUI2K4.UT2K4InGameChat
StatsPromptMenuClass=GUI2K4.UT2K4StatsPrompt
MusicManagerClassName=GUI2K4.StreamPlayer
WaitingGameClassName=
NeedPasswordMenuClass=GUI2K4.UT2K4GetPassword
ServerInfoMenu=KFInterface.KFGUIServerInfo
SteamLoginMenuClass=ROInterface.ROSteamLoginPage
ConsoleHotKey=192
I don't really see which of those it could be that broke my maplist config though. Oh well, I've got it all sorted now regardless.
So, for future reference, if anyone would happen to get this issue, all you have to do is delete your KillingFloor.ini in \Steam\steamapps\common\killingfloor\System\ and start the game again, and you should be able to create functioning maplists again.
PS. I found another difference between the .ini files. The old one had
DetectedVideoMemory=1024 while the new one has
DetectedVideoMemory=512. Might that be because my current GPU has 896 MB RAM and that Killing Floor doesn't really know what to make of it? (Win7 x64 with 4 GB DDR2 RAM as well) And should I change it to 1024 again, would it make any difference?
Sorry for the awfully long post.