When designing queries in Dynamics NAV you’ll get an error i CSide if you include a BLOB field, but no error if you include a MediaSet field. At runtime, you’ll get this strange error:
Unable to compare operands of type NSMediaSetWrapper with NavMediaDescriptionCollection.
Remove your MediaSet field from the Query Object and everything works again.
Att Microsoft: Perhaps expand the BLOB check in FINSQL.EXE to include MediaSet fields also 🙂
Blog entry to serve as hit for googling this error