Pretty much all modifications out there are created by people from all over the place, and the quality as well as reliability can vary a lot. :P
Could just be that there is a problem with the mod itself, rather than the way in which you installed it.
Hopefully you are using a mod installer which may speed up + help a lot with the whole process. Just remember to back things up, and I usually try out any mods first in single player before moving onto VC:MP. Even so, the results can vary between single player and multiplayer (which in itself is really a mod to a certain extent).