LabVIEW 7 can't open source code based on the LAbVIEW 6.1 with an error that some VI doesn't have block diagram and can't be converted. What to do in this situation.
You are stuck, unless you can get the source code for the VI with the missing diagram. However, you can still open the rest of the application. Delete the "bad" VI and replace it will new code, assuming that you know how it works.
There is no way of converting/upgrading a VI to the newer version of LabVIEW without its block diagram. Below are a couple of KBs that discuss this issue:
