crash trying to open options

Hi,
after installing the extension I was able to edit the options but now if I click on options Firefox crashes.
I'm using
Mozilla/5.0 (X11; U; Linux x86_64; it; rv:1.8.1.3) Gecko/20070310 Iceweasel/2.0.0.3 (Debian-2.0.0.3-1)

and I get the following error
GCJ PLUGIN: thread 0x14a6590: NP_GetMIMEDescription
GCJ PLUGIN: thread 0x14a6590: NP_GetMIMEDescription return
GCJ PLUGIN: thread 0x14a6590: NP_GetValue
GCJ PLUGIN: thread 0x14a6590: NP_GetValue: returning plugin name.
GCJ PLUGIN: thread 0x14a6590: NP_GetValue return
GCJ PLUGIN: thread 0x14a6590: NP_GetValue
GCJ PLUGIN: thread 0x14a6590: NP_GetValue: returning plugin description.
GCJ PLUGIN: thread 0x14a6590: NP_GetValue return
/usr/share/themes/Clearlooks/gtk-2.0/gtkrc:34: error: unexpected character `@', expected string constant

(npviewer.bin:31951): Gtk-CRITICAL **: gtk_window_resize: assertion `width > 0' failed
The program 'npviewer.bin' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 10071 error_code 3 request_code 3 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)
Segmentation fault