Upgrade from 4.2.12 to 4.4.2 fails

Hi Everyone,
Recently I am trying to upgrade from 4.2.12 to 4.4.2 but unfortunately I keep getting this issue

Attempt to reload RT/Squish/CSS.pm aborted. Compilation failed in require at /rt/lib/RT/Interface/Web.pm line 84. Stack: [/rt/lib/RT/Interface/Web.pm:84] [/rt/share/html/Elements/Header:139] [/rt/share/html/Elements/Login:49] [/rt/share/html/NoAuth/Login.html:56] [/rt/lib/RT/Interface/Web.pm:354] [/rt/share/html/autohandler:53]

I think the problem could be with the way the .pm files are placed in their directory. I have tried to move around .pm files and tried to put them in places from where RT is trying to look for but no luck.

Any suggestions?