Well - since it's complaining about "LDREDIRECT.DLL" - is that one present? The way I read the error, that's what we're having problems finding
It should normally live in "C:\PROGRAM FILES\LANDesk\LDCLIENT\" ...
It sounds like either the file isn't there, or we're having problems accessing it (check NTFS permissions)? Compare against a healthy client. A Filemon trace might be interesting (push come to shove) - should show you if we're running into problems trying to access LDREDIRECT.DLL
Also - remember that if you run stuff yourself, you're running it - I guess - as local admin, while LANDesk would normally execute as local system.
Hope this gets you started in the right direction.
LANDesk EMEA Technical Lead