With LV7 National Instruments stopped supporting the serpdrv based serial IO VIs, the ones you seem to have been using. To not break the code of old VIs they have made a set of VISA based VIs that have the same names as the old serial compatability VIs and when you open up your application for the first time in LV7 some of the VIs might be loaded from those VISA based VIs, and some might be loaded from your llb file where you have included old serial VIs...if that happens you might get a mixture of incompatible VIs.
Personally I saved all the old serial VIs from LV6.1 with new names and have replaced the serial VIs with those..that way LV7 never replace them with anything form the vi.lib, however you can also make a lib of the old files in LV6.1 and then repl
ace the lib that comes with LV7 containing the VISA based ones with that one...that way you do not need to do anything with all your old code, on the other hand it might introduce problems if you move it to another machine with LV7 that this trick has not been done on. To avoid getting error 37 you need to copy the serpdrv file from your previous LV to the LV7 directory...error 37 means that it could not find the serpdrv file.
An alternative off course is to switch to the VISA based replacement VIs...or to pure VISA code (no wrappers to simulate the old serpdrv VIs). The downside to that is that you'll need to include the VISA runtime engine with your application. NI has made this easier than before; just check the serial IO support option in the app builder...however if you want to make your own installer with a third-party tool the old serpdrv way of doing things is easier, requires less space on the hard drive and avoids the name National Instruments from showing during installat
ion...
