One thing I found handy to do when first installing ISBoxer is load up the team, turn on mouse and key repeater, bring up the Key Bindings menu in the Blizzard help menu and turn off every single in-game configured key binding I didn't specifically use (with the mouse repeater on, it means everyone in the team will unbind all the same keys).

Handy to do for later when you start building keymaps as it avoids you inadvertently assigning a keymap a key combination that one or more members of your team already has bound in-game.

As Lax said, most follow issues boil down to one or more members of the team having a conflicting in-game versus ISBoxer key assignment.