Anything that is not in the form of: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx where x is a hexadecimal value (e.g. 0-9 A-F) is going to fail... are c.evs_OrderIDid and b.ORdernumber formatted like that?
why do you need to make this conversion? Seems odd that you would need to do that...
-- Itzik Ben-Gan 2001