Avoid discarding preferences.xml because of bad Location string

Inkscape has just informed me that preferences.xml are invalid and that defaults will be used instead. Examining output from terminal clearly showed that problem is non-readable USB stick device name on Linux (it was formated and named strangely by someone on Win).
Entity: line 661: parser error : invalid character in attribute value
       path="/media//firma/" />

problem was character between strings "/media/" and "/firma/". Although I could open/save files from device, on next Inkscape startup problem poped up. Although problem exists, it's unfair to strike user with error message when it's not his fault.