To be able to successfully load a VI with the LabVIEW Runtime Engie in Teststand, the VI and all its dependencies need to be available in the right version. Especially after upgrading to a new LabVIEW version, old projects might not be completely upgraded. There are 2 options to solve this issue.
1. (Preferred) Source Distribution
of the VIs in question.
2. Mass compile
the whole directory of the VIs in question.