Cubase 4 not exporting WAV

It appears that my version of Cubase doesn’t want to handle WAV files at all.

I now can’t import them either, and often when I click on a channel, I’ll get a message saying ‘could not create record file’.

Does anyone know what could have happened to cause this, as it now make this version of Cubase completely unusable and I don’t want to lose the years and year of projects I’ve made.