I noticed while messing around if i enable a logged in client to have "WSP+PED" (so wholesale prices and a percentage discount) everything works fine on product pages / cart etc... but get an error on the search.asp page
The ORDER BY expression (0.95*pWholesalePrice) includes fields that are not selected by the query. Only those fields requested in the first query can be included in an ORDER BY expression.
Ok, I've tried here with a JET database connection and settings that would cause the ordering that is causing your problem and I still can't get this to go wrong. Could you possibly try a connection string of this form though to see if that helps?