Hammer/Sprites/CS directoryPut it where?!?!
"Mod-NumforName: xxxx.mdl not found"
Often because the cycler entity, cyler sprite or some other entity used has the wrong path/name. You must use the perfect path/name, with the right capitals - or it will stop the game. The path should start with model/modelname, not the whole path name. Sometimes browsing to the model works best, sometimes typing the path/name in works best.
Also if you have changed the model, for example a new player model or a new gib model, it can cause this problem. Re-install the old model.
Sometimes the "too many wads" problem sets this off too.