Does this happen if you set up your own server? NQ is also ETPub based. It reall doesn't make much sense that it happens in ETPub and in silEnT but not with other mods. You should install the game outside of the "Program Files (x86)" and not run it as an admin, it would give you at least a little better security. Overall, you shouldn't run programs as admin unless they really do have some serious reason they would need it. Please try to set up your own server locally and test connecting to it. Server:
...\etded.exe +set dedicated 2 +set fs_game silent +map oasis
Client:
...\et.exe +connect 127.0.0.1