The crash is a problem with the Flash plugin.

You can check for problems caused by recent Flash updates and try these:

• disable a possible RealPlayer Browser Record Plugin extension for Firefox and update the RealPlayer if installed
• disable protected mode in Flash 11.3 and later
• disable hardware acceleration in the Flash plugin
• downgrade the Flash player to version 10.3 or 11.2

• http://kb.mozillazine.org/Flash#Troubleshooting
• http://helpx.adobe.com/flash-player/kb/flash-player-113-crash-mozilla.html

Thank you cor-el. Yes, my preblem is solved. I went to the Real Player and disabled the web download and recording. After I restarted the firefox, I am now able to read pdf files in firefox.

thanks once again.

Fiseha