Generally speaking the code itself will not change by storing on a new server or moving the pages in the site around, but sometimes the way servers are configured can make pages behave slightly differently. I'm not sure if that is the case for you.
To be able to get to the bottom of this we would need to be able to see and test the pages that are working on the previous server and compare them to the non working on the new server.
If you open the DataAssist Search server behavior you should be able to see the column type value here, if what you see here does not match what you have in the code please let us know so we can look into the issue further.
