MOSS is unable to reach SharedServices1_DB

"Unable to connect to SQL Server session database. The connection string ( .. ) was returned by an instance of the IPartitionResolver .. "

Your newly installed webpart is bitching that it cannot reach a "SharedServices1_DB" database?
Thanks to Sunil, try the following steps:

"1. On my SQL Server 2005 Management Studio,
2. Goto Security --> Logins --> you can find the user that represents web server, DOMAIN\MACHINE$.
2. Right-click the DOMAIN\MACHINE$, choose User Mapping.
3. Map the SharedServices1_DB. check the roles db_owner and public.
4. Click OK."

Now, understanding the implications is another matter, let don't mix concerns ..