SQLCe connection error 0x80004005

I get an error when I'm trying to open a database in PocketPC emulator or from the program with connection's Open() method (C#). Here it is:

Internal error: SQL Server Compact made an unsupported request to the host operating system.

Can someone explain what can cause this error to appear?

The database and application are on Storage Card (shared folder from PC, on which Everyone has read/write permissions).

Edit:

FOUND that its because of storing DB on Storage Card开发者_高级运维 (after moving database to 'My Documents' error disappears), but still don't know the reason of error.

Think there was a buggy operating system installed on my PPC. Because after reinstalling it SqlQuery analizer started to work normally and the error has gone.