According to Tommy's error page the wav-sound can't be longer than 3 minutes.

so if its not more than 3 minutes long itll probably work??

I cannot hear my wavs or Warning: Unable to open sound/C for transfer or com_loadfile: bad usehonk

Wavs are tricky. You must use the perfect path/name, with the right capitals; sometimes even just adding or dropping the .wav extension in the name can fix things. If there are many wavs, you have to watch your sound card channel limits, or you will lose sounds/ambient_generics/wavs. If the problem is a custom wav, it has to be under the max size limit of less than 3 minutes, in the right format. (format is: unsigned, 8bit, mono, one start cue, 11025Hz PCM.)
You can also try typing developer 3 into the console while playing the map, then walking through a trigger that targets the wav. The report may give a hint as to what is wrong.

(Source: Tommy's error page)