You’ll have to add the 5.0 objects for the stylesheets to get that working. There are a number of posts on this subject on this forum and on mibuso. Take a look around the search and let us knkow if you can’t find it.
I am using NAV 2009 R2 and I was experiencing the same problem while exporting G\L Entries. To resolve the problem, I opened up NAV 2009 Cronus database and copied the contents of tables 2000000065, and 2000000066 to my current installation.