As guide I use this article http://msdn.microsoft.com/en-us/library/bb668969.aspx
After step 3 (Analyzing sourcesafe folder) I have file VSSAnalysisReport.xml which tell me in summary that I have 6350 warnings (project is really large) and 1 error.
And this single error not descriptive very much. Whole XML-node with this error looks like
<Issue IssueID="SourceSafeQfeNotInstalledIssue" Type="Error">
<Message />
</Issue>
Who knows this error? Of course I have installed sourcesafe and no clue what this error could mean.
Sorry. I should have done my homework more carefully. I just need to install hotfix in order to eliminate such problem. Hotfix is here http://archive.msdn.microsoft.com/KB950185/Release/ProjectReleases.aspx?ReleaseId=1123