problem whit thanks plugin

[LittleGirl]

i use thanks plugin ver 3.9.1 over mybb ver 1.4.13
when i active this plugin....cant open downloaded files (attach files)
but when deactive it all files open easily
plz help me

for example...
when plugin thanks is active and download a zip file....  windows cant open zip and says:
The archive is either in unknown format or damaged