Refresh Error

Hi,

I have an issue with one of my reports. I tried to refresh the data behind it, but it gives me this error:

Does anyone knows how to exactly find out what it is going on in the background?

I read posts about this, but i cant seem to understand where i need to look to correct the error 

[more than one table has this error - not just SALES]

I really would like to avoid building the report from scratch, so any suggestion is very welcome.

Kind regards,

Alessandra