We have ran into a few circumstances where project repositories have been corrupted in TimeXtender. The issue at hand was due to multiple developers making changes on concurrent tables. While i understand that due diligence in development management can mitigate the risk of overwriting other developer's work, its just too easy to corrupt the repository in this manner.
one instance was due to a TimeXtender variable being altered, in which was utilized throughout multiple sections of the data warehouse. this change to the variable corrupted the entire repository and since the client is in a high security environment, we could not ship off a backup of the repository for TimeXtender to fix. We ended up restoring the database and lost almost a week of work due to this.
some kind of locking and versioning, such as Tortoise SVN, would be instrumental in making the product more reliable.