Gmail-0.7.6 Module in Network

[CyberFox]

The module GMail 
0.7.6(Gmail-0.7.6<http://downloads.mozdev.org/webmail/gmail-0-7-6.xpi>) 
does not work properly with "Thunderbird PortableApps 15.x" under network. 
Ex: \\Server\ThunderbirdPortableApps (directory on the network).
GMail 0.7.6 always asks to install when I start Thunderbird. Please help me 
out!!  Thank you!