When executing a script in TOAD the following command
define prv = 6606IN0006 values substitution variable prv as a number 6606 while it should be alphanumeric 6606IN0006.
This behaves differently from SQL-PLUS.
WORKAROUND
Surround the variable with single quotes e.g. define prv = 6606IN0006
STATUS
Waiting for fix in a future release of Toad for Oracle