Problem connecting to Sql Server 2005 on Vista From XP Home

I am attempting to connect to a copy of Microsoft Office Accounting 2009 (running on Vista 64) from a laptop running XP home. I have done all of the MS steps (create user on Vista with same username and password, etc) and I can access files on the workstation from the laptop.

However, when I try to access the MS Accounting file I get the following error message

"The company could not be opened or access was denied. Please ensure that access has been granted and that the company database exists."

I then check the event log on the Vista 64 machine and get the following tidbits of information

SSPI handshake failed with error code 0x8009030c while establishing a connection with integrated security; the connection has been closed. [CLIENT: 192.XXX.X.XXX]

Any ideas anyone?

First off, Vista has specific security requirements for SQL 2005. Look into that. Install SQL 2005 SP2 or SP3 if you haven't already.

Secondly, check whether your SQL instance allows Windows authentication.

Finally, check whether the local Windows user has access to SQL and the necessary execute permissions. SSPI uses the credentials of the logged-in user.

There is a possible workaround, which I don't recommend: add a SQL user and change the connection string (if you can) to use this SQL user. That will bypass SSPI entirely. SQL has to be running in mixed mode, though.