No; my problem (both with the other program, a while back, and with Panda 1.5.3) is on Windows XP (SP 2 back then, SP 3 now).
I recall that the work-around, back then, had to do with the difference between different registry key types (SZ_EXPAND vs SZ_STRING or something like that). I think the installer tried to get the path of type SZ_STRING, and when that failed, assumed the path was empty, and overwrote its own path. You have to try for several of the string types to properly retrieve the system path environment variable (or, really, any environment variable). I also don’t think NSIS does the right thing here (whereas I think WiX does 