I don't want to hi-jack this thread but I have an issue with vqmod that might be similar to OP.
Working with OC 18.104.22.168 on a Synology server with Apache 2.2, PHP 5.6 and MariaDB 5
I downloaded latest version on github (2.6.3), unzipped and uploaded to my server (root folder of the site). Set permissions to 777 (for the time being) and went to [my_sites_url]/vqmod/install. The module reported that it had installed without problems. Went to the admin panel -> modifications and refreshed the modules section. It did not appear. Went back to [my_sites_url]/vqmod/install and vqmod stated it had already been installed on my site.
Tried to install vqmod manager as per instructions from @straightlight but the manager also does not show up. I must be missing here something (and I am short of "bright moments" for this year
Any help greatly appreciated!
EDIT: No entries in the error log