Old versions of NAV don't remove certain registry entries, which can muck up Java script operations. The symptoms you describe match this exactly.
Here is the answer ..........
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BACK UP YOUR REGISTRY FIRST THOUGH.HOW TO BACK UP REGISTRY
http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/199762382617?OpenDocument&src=sec_doc_nam=======================================================
The fix is to correct the registry entry.
Copy the text between the ----- markers into a text file in Notepad,
save it as "Jscript.reg" to your desktop, right-click the file and
choose Merge.
Ensure that your Windows directory is indeed c:\windows - if not edit
the text BEFORE you Merge it to reflect the location of your Windows
directory.
Remember that the directory separator \ needs to be written as \\.
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Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\CLSID\{f414c260-6ac0-11cf-b6d1-00aa00bbbb58}\InprocServer32]
@="c:\\windows\\system32\\jscript.dll"
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