I get an error: reading or writing to disk, etc. when trying to export

Hi out there,

I have been getting this error constantly: audition has encountered an error reading or writing, etc as mentioned above, recommends saving etc and restarting. It doesn't help. 

I recorded some local gospel singers and am just mixing in some beats for them, etc.  I have had this error before.  any ideas on how to fix this?  i hate to lose so much work.

thanks, and asante sana, greetings from Tanzania