Error 90101 USB communication

[MCH170]

Hello, I am trying to communicate with the Newport Oriel Cornerstone 260 monochromator via USB. I used its premade VIs to initialize the communication but I keep getting error 90101 "LabVIEW could not return a string from the shared library call". Any ideas? Thanks for your time.

[altenbach]

An image of a truncated block diagram containing two generic icons is probably insufficient for us to troubleshoot your problem.

[MCH170]

You're right, sorry about that. Here is the full program (Data_output is the main one), all necessary VIs and dlls are included in one of the 2 folders. Also here is a device manager screenshot of the monochromator driver. Anything else you might need I am happy to send. Thanks for your help.