I have a problem like this. Please help.An error occurred while reading from the store provider's data reader.See the inner exception for detalis

[Memo]

You’ll have to get V4 running off of SQL Server before migrating to V5.

I found this thread, perhaps it will help (backup database file somewhere before attempting anything):

Converting Compact SQL database to SQL Express (script)

This collection of scripts will convert a Compact SQL (*.sdf) database to SQL Express 2012 database and update SambaPOS to use the database. Requirements 1… SambaPOS should be working using the Compact SQL database -> SambaPOS4.sdf 2… Install SQL Express 2012 exactly as documented here - DO NOT follow step 4. Using SQL Express 2012. and do not run SambaPOS after installing SQL Express. 3… Locate SambaPOS4.sdf and place all of the files from the attached ZIP file into this location. The locat…