Posting to Gen. Journal delete permissions?

Using NAV 2009 SP1

Why would a user need delete permissions to the General Journal Line to post a journal entry?

Because GJLines ARE deleted after posting.

Do not confuse General Journal with General Ledger, journals are only “working” tables, so DELETE permissions don’t cause any harm, on the contrary, those must be present for normal Navision workflow.

Ah ok thanks, is there any good whitepapers on navision financials?

CustomerSource has tons of different materials, if you are an enduser on active maintenance plan, you are eligible to access it.