Could not load file or assembly 'ADODB, Version=7.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

This error usually happens on 64-bit platforms for connections with SQL Server Native Client driver. You can often solve it by following these steps:

1. in Windows folder create directory "assembly\GAC\ADODB\7.0.3300.0__b03f5f7f11d50a3a" (for example: C:\WINDOWS\assembly\GAC\ADODB\7.0.3300.0__b03f5f7f11d50a3a)
2. Download ADODB.dll. It included to Office XP Primary Interop Assemblies (1.7 MB) and can be downloaded from page: http://www.microsoft.com/downloads/details.aspx?FamilyId=C41BD61E-3060-4F71-A6B4-01FEBA508E52&displaylang=en
3. Copy ADODB.dll to the created directory.