Regsvr32 is generally for registering and unregistering the objects
found in COM dlls (although there's nothing to stop you putting other
initialisation stuff in there). Mysql++ is not a COM dll and neither
does it have the DllRegisterServer or DllUnregisterServer entry points,
so regsvr32 will fail even if LoadLibrary works. What are you trying to
achieve by registering it?
As for why LoadLibrary fails, don't know - it could be any number of
reasons (http://msdn2.microsoft.com/en-us/library/ms684175.aspx). Maybe
it's trying to call the DllMain entry point function, which again is not
found in mysql++.
This page http://support.microsoft.com/kb/207132 has source code for a
regsvr32 application. Maybe you could use that to diagnose your