Firebird Server and .NET Provider Incompatibility

Since my drive crashed the other day, I've had to reinstall my drivers. I've been having problems with my old applications written on Visual Studio .NET 2003 that uses the Firebird .NET Provider 1.6.x and 1.7.x. When I ran them, they would get really strange errors in the conn.Open() call.

After uninstalling and reinstalling the .NET Providers, I eventually tried uninstalling Firebird 2.x and re-installed the older Firebird 1.5 server. Voila - it worked! It seems that these old .NET Providers only work with the older Firebird server also. In contrast, the FirebirdClient 2.0.x providers for .NET 2.0 worked with both 1.5 and 2.0 servers.