Don't know if this helps, but I got this error after installing VC++
1.5 on my machine to rework an old application overwrote the
sqlsrv32.dll with an older version. This screwed up Enterprise
Manager and Query Analyser big time and reinstalling MDAC - even
reinstalling SQL Server Client Tools - didn't help. In the end all I
had to do, though, was copy the correct version of this dll over from
another machine. It seems to be working OK now.