Howto fix Internet Download Manager Add On for mozilla 14 or more

if you update the latest version of the IDM mozilla add-ons for too long you will be spelled out version. then you need to update your mozilla add-ons IDM. here add-ons IDM for version 14 and above.
step:
1. open mozilla. Go to Tools > Add-ons

Add-ons dialog should open. Click on "Extensions" tab and find IDM CC

2. Uninstal Add-ons IDM CC.
3. Instal new add-ons IDM CC
DOWNLOAD FILE
4. Instal and done...

source : IDM Intergration