newID() not working against starrez

I’m having an issue, but it’s being masked by the fact I’m doing a REST POST against the starrez system (residential housing). I’m just trying to do a simple SELECT [field1], [field2], newID()… Whenever I add the newID() as myGUID back in, my POST fails. I’ve tried several different forms of variations of getting a GUID (Oracle, SQL Server, etc…) since I don’t know what format their (starrez’s) database is in. Any ideas?