It has recently come to our attention that after installing Windows 7 Service Pack 1 users were experiencing a certain error, preventing them from using the TractBuilder Tools for ArcGIS. This error is caused by changes made to the mscorwks.dll file, a part of the .Net framework v2. Hotfix KB974372 is the part of Win7 SP1 responsible for these changes. We are working on a permanent solution, but for now users can download and replace (with the help of IT and/or our support staff) mscorwks.dll with the previous version. For assistance please contact us at support@tractbuilder.com.

UPDATE: This issue has been resolved.