Sorry guys for bumping up this thread again but this error seems to be beyond me this time. A simple access to a table with column index is somehow not working :@
The only explanation I can think of is that there is some leftover stuff in the row index (column 0). Please activate the row index and check if that column has the index "PrioID". If this is the case, please delete the index and the content of column 0 and then deactivate the row index.
If the row index is empty, I have no idea what is going wrong. If you upload your model I will take a look at it.