I would agree with Winterfire if it was just the menu, but it seem strange that it would also make the game skip.
The skip feature is triggered by the Control keys, do you use a keyboard that need you to press them for a reason or another ?
Is there any way that you had a controller or some other external device mapped to the "Tab" key? (i.e., from a hotkey or macros perspective)
As pointed out by AON, the control key skips text in RenPy games, but in addition, the Tab key does it automatically without needing to press and hold down the CTRL key.