[bugfix] provide better error message if imported XQuery source could not be loaded.
[bugfix] provide better error message if imported XQuery source could not be loaded.

svn path=/trunk/eXist/; revision=10529

ambs/exist,shabanovd/exist,wolfgangmm/exist,ljo/exist,hungerburg/exist,patczar/exist,patczar/exist,wolfgangmm/exist,eXist-db/exist,ljo/exist,dizzzz/exist,shabanovd/exist,adamretter/exist,jessealama/exist,joewiz/exist,jessealama/exist,joewiz/exist,opax/exist,adamretter/exist,jensopetersen/exist,shabanovd/exist,patczar/exist,shabanovd/exist,ambs/exist,jessealama/exist,windauer/exist,wolfgangmm/exist,opax/exist,windauer/exist,MjAbuz/exist,olvidalo/exist,hungerburg/exist,joewiz/exist,zwobit/exist,lcahlander/exist,lcahlander/exist,dizzzz/exist,wolfgangmm/exist,RemiKoutcherawy/exist,kohsah/exist,zwobit/exist,ljo/exist,wshager/exist,wshager/exist,RemiKoutcherawy/exist,lcahlander/exist,ambs/exist,jensopetersen/exist,lcahlander/exist,wshager/exist,olvidalo/exist,windauer/exist,joewiz/exist,ljo/exist,zwobit/exist,opax/exist,eXist-db/exist,kohsah/exist,RemiKoutcherawy/exist,windauer/exist,MjAbuz/exist,jensopetersen/exist,patczar/exist,eXist-db/exist,RemiKoutcherawy/exist,dizzzz/exist,zwobit/exist,lcahlander/exist,ambs/exist,jensopetersen/exist,MjAbuz/exist,eXist-db/exist,windauer/exist,MjAbuz/exist,shabanovd/exist,wolfgangmm/exist,opax/exist,RemiKoutcherawy/exist,jensopetersen/exist,jessealama/exist,ljo/exist,hungerburg/exist,patczar/exist,zwobit/exist,adamretter/exist,eXist-db/exist,dizzzz/exist,lcahlander/exist,dizzzz/exist,olvidalo/exist,jensopetersen/exist,wolfgangmm/exist,kohsah/exist,MjAbuz/exist,olvidalo/exist,patczar/exist,kohsah/exist,olvidalo/exist,jessealama/exist,hungerburg/exist,jessealama/exist,joewiz/exist,kohsah/exist,shabanovd/exist,dizzzz/exist,ljo/exist,wshager/exist,kohsah/exist,ambs/exist,joewiz/exist,wshager/exist,wshager/exist,windauer/exist,MjAbuz/exist,RemiKoutcherawy/exist,ambs/exist,adamretter/exist,adamretter/exist,adamretter/exist,eXist-db/exist,hungerburg/exist,zwobit/exist,opax/exist