Incoming calls leaving a plus sign on the caller ID

If I call my extension from my cell phone it works, the caller ID though that is left on my phone has a plus sign in it. So when I go to redial it I get the following error.

== Using SIP RTP CoS mark 5
[2012-11-14 14:53:44] NOTICE[4547]: chan_sip.c:22798 handle_request_invite: Call from ‘100’ ( to extension ‘+5555555555’ rejected because extension not found in context ‘from-internal’.

The following links talk about the situation but seem difficult to implement.

For my outbound route on the dial plan I used the wizard to pick most of them except lookup local prefix and the CSV one.

Can someone provide direction on how to resolve this in the easiest manner.