can't intstall web clipper in firefox

[pbotu 1]

fail on intstall web clipper in firefox due to cann't modify the needed file.

 

already done the below and still not worked:

1. upgrade firefox to the latest version
2. restart firefox under safe model
3. reset firefox

really need help!  appreciate it!

 

 

 

btw, web clipper for firefox abviousely need update, compares to chrome......