This is the kind of the thing you don’t want to see when you check out a project from SVN that should be compiling. It took a moment of thinking and a bit of reflectoring to find that the method was internal in the dll I was using:

SQL SMO TriggerCollection in reflector

The TriggerCollection is part of the table object in SQL Management Objects. I had the identical project compiling on a different PC. The funny thing was that the versions of the dll were identical. Only in reflector did I see a different version Guid:

// Assembly Microsoft.SqlServer.Smo, Version
Location: c:\Programme\Microsoft SQL Server\90\SDK\Assemblies\Microsoft.SqlServer.Smo.dll
Name: Microsoft.SqlServer.Smo, Version=, Culture=neutral, PublicKeyToken=89845dcd8080cc91
Type: Library

// Module Microsoft.SqlServer.Smo.dll
Version: b74f0ed4-1269-420b-b67e-8bbae0c9c035
Location: c:\Programme\Microsoft SQL Server\90\SDK\Assemblies\Microsoft.SqlServer.Smo.dll
Size: 1555232 Bytes

This led me to think about the service pack level installed and I noticed you need Service Pack 2 to be able to use the Add method publically. (At least it wasn’t the other way round, they could had made it internal in the newer service pack *G*. Thankfully not.) Case solved, back to getting through this pile of work…