Looking at your list of things done before installing subsim's PA I don't see that you applied the official 1.1 patch for Silent Hunter 2
Did you patch to 1.1 before installing PA?
The patches and glitch fixes to PA are not essential to gameplay, they update the mod and fix minor bugs, but the original release should work anyway by itself.
The janus error you get tells that a unit is missing when SH2-PA tries to load a mission. That missing unit could come from either the 1.1 official patch install missing, or any problem/malfunction in the PA mod you downloaded. This one is not likely to happen, but you can easily test if the mod in general works by trying different missions from the single mission menu and seeing if all, some or none do work.
Assoon as you answer the 1.1 patch issue and tell me if the single missions work, I might be able to help your further
Note all janus errors you get and also copy them here, they help diagnosing the problem
