A: 

According to the apache docu the syntax is as folows:

Redirect 301 /service http://foo2.bar.com/service

So try:

Redirect 301 /pi/Dækkape_UG150_12_lysegrå_5302_.aspx http://www.el-netsalg.dk/pi/Dækkape_UG150_12_lysegrå_5271_.aspx

without the "http://www.el-netshop.dk" for the old-path paramater.

JochenJung
Removed the http://www.el-netshop.dk but it still not working. Also Im unable to access the page without www, but thats not so important.I uploaded my complete htaccess fil if its helps.http://pp-nethandel.dk/test/htaccesselnetshop.txt
gulbaek
Try with a capital R in Redirect. I think this is important.
JochenJung
Thx JochenJung but its still not working :-( Would be nice with some software to help building a working redirect.
gulbaek