File icon is not displaying properly. Please help!

Hi, I have updated Dolphin module from 7.0.9 to 7.1.
But I am having problem with File module.
File icon is displaying properly with dolphin demo site but not mine.
All file icons are displaying as "?". Why??
I have no idea to display icon properly.
I have uploaded PDF and GIF file but there is no PDF and GIF icons. It displays only "?" icons.
Please give me an advice to solve this problem. Thank you!

Yes, that is what is displayed on mine as well.

I have uninstalled file module and tried to install again(Files version 1.1.1 ) but  now I get an error. "The module is not compatible with your version of Dolphin script"
I have not done anything with this after I have upgraded to Dolphin 7.1.0.
Please help.

have you tried deleting the Dolphin module from your site via FTP,  downloading Dolphin again and re-uploading the Files module?

It seems the File module you have is the one for 7.0.x so this will make sure you have the correct version

I think there were some upgrade problem. So I think problem will solve. Thank you!!