Came across this error this morning when trying to import the latest customisations from our test server to a production server.
This was due to the field kal_pobox being deleted on the test server (as a nvarchar field) and recreated as a decimal…), however you don’t know that yet when you get this error (it doesn’t tell you which one!)
In order to find the field you need to list the attributes for the offending entity side by side, sort them by type and look for the first attribute type in the error on the destination system (in this case a nvarchar) and see if it is in the source attributes as the same type, if not look in the second type in the error (decimal) and you should see the attribute that’s causing the problems.
If you’re lucky, then its only one!
The resolution is to delete the attribute in the destination system and let the source customisations reinstall it. Alternatively you could change it back on the source system to match up as deleting attributes is not always advised as they may have data in them!