is this happening for only data source? is it full load?
in such case try to use selections at info pack and load data into bw.
at BW side ,have you doing house keeping activities?
Even you need to check about BW space.
But by seeing above error, there might some issue about partner profiles/idocs issue.
Try to replicate data source into bw and activate it.
Later try to activate psa table thru SE14.