[Inkscape-user] Error message guidelines

When I make a guideline and I want to dubbleclick on it to position it exactly I get a dialog window to fill in the exact position. But I also get a DOS box with the following errormassage:

** (inkscape.exe:3476): CRITICAL **: file helper/unit-menu.cpp: line 294 (void s p_unit_selector_set_unit(SPUnitSelector*, const SPUnit*)): assertion `pos >= 0' failed

Closing this DOS box will automaticly close Inkscape. However, if I leave this DOSbox open I can just continue working with positioning guidelines as if nothing happens. So not closing the DOSbox is a way to work with the guidelines. Still I think something CRITICAL is going wrong. Can anyone tell me what the problem is here.