I open Order Entry, put in a customer, then do a lookup for an inventory item, put in the quantity and click Post. At this point I get the invalid database specification message. I can go through the same basic steps for a purchase order and it successfully posts. 

Hi Rob, If all your config is identical to production, and it works in production, then as you would be thinking, it should work in Dev too.  Using a different connection method/ODBC driver than recommended can cause problems like this so I do recommend working through the Admin guide I posted earlier.  The connection from Sage 300 to the Databases isn't it just works or it doesn't - you can make a connection and some things work and others don't based on the interpretation of driver - I have seen this before.  If you run the RVSPY logger from the RUNTIME folder it might give you the underlying error but it likely won't make sense as I suspect it will be a driver issue.  I thought about a table permissions issue too, but that would be very odd.  Overall all I can suggest is engaging a Sage Business Partner from here.

I'm wondering if Ops Inquiry is causing your issue.

If you're comfortable, edit the CSAPP table and remove the UQ record to test. 

I'm wondering if Ops Inquiry is causing your issue.

If you're comfortable, edit the CSAPP table and remove the UQ record to test. 

Nope.