Value does not fall within the expected range

My first SharePoint 2010 post!

We're in the process of deploying a supplier management system to a client, this after extensive testing first on our staging environment and then on theirs. Everything was working fine until we started doing data migration testing.

The client had been chucking in data and then wiping it out again repeatably on their server, but then we started getting a System.ArgumentException: Value does not fall within the expected range error on a section that had previously worked.

Much googling later, everything I found indicated that the List View Lookup Threshold needed to be changed. I knew for a fact that this was not the issue as the system worked as expected on our server and our setting was set at the default of 8.

This made me look at what was getting written to the main list. There I found that a required value was now showing as blank. The column in question was a lookup to another list. Investigating the log file a little further up indicated that the system was unable to open a lookup list >

Armed with the the GUID from the log, I could see that the lookup list was not the same. I then pointed the client's admin to the possibility that the lookup column may have become disassociated from the list.

They responded that they had in fact deleted the lookup list and re-created it from a template containing the lookup values during their importing trials. Because the lists for this system are created pragmatically and activated via a feature, they have specific GUIDs. The client was then able to delete all the lists and recreate them via the feature and it all started working again.