Enable plugin nppdf.so in firefox?

[cblasius]

Hello!

I've a problem with plugin to view PDF file in firefox. Could someone 
help me?

Wehen I run firefox from command line I obtain this message:

LoadPlugin: failed to initialize shared library 
/usr/X11R6/Adobe/Acrobat7.0/ENU/Browser/intellinux/nppdf.so 
[/usr/X11R6/Adobe/Acrobat7.0/ENU/Browser/intellinux/nppdf.so: Undefined 
symbol "XtCalloc"]

Best regards,
cblasius