I see this is a pretty common error, but I'm still not able to solve it. I have a SharePoint 2010 site collection in my prod environment, which I backed up using the stsadm backup command, and I'm trying to restore it to my beta environment to an existing sharepoint site using stsadmin restore with the -overwrite parameter. When I run the restore command I get this error:
The operation that you are attempting to perform cannot be completed successfull y. No content databases in the web application were available to store your sit e collection. The existing content databases may have reached the maximum numbe r of site collections, or be set to read-only, or be offline, or may already con tain a copy of this site collection. Create another content database for the We b application and then try the operation again.
Microsoft has 2 methods for resolution posted below, and I'm trying method 2, however that does not help: http://support.microsoft.com/kb/926321