SSE Provider did not find the database file specified in the connection string - using membership provider

Hi i am receiving this error when trying to use my membership provider: After googling the error most peoples problems are fixed by removing the old connection string first but this has not worked for me.
I have used a simple custom memberhip provider with one table.
On shared hosting with 123-reg.
Any ideas how to resolve? 

The SSE Provider did not find the database file specified in the connection string. At the configured trust level (below High trust level), the SSE provider can not automatically create the database file. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and w ...