Replace the RsCur with a DLookup...
strDBCura = "Update " & RsType!sobpdebit & " set DebitDBN = Debits * " & DLookup("CUR","CURRFG", "SOBP = '" & RsType!SOBP & "';"
I wrapped the criteria of the DLookup with single quotes, assuming it was a string, if it's a number, remove them...