Hi mate,
If you can change from 1st to 2nd in tiptronic ie lever pushed to the far left of 'D' and its fine,then its prob a computer/paddle fault and not gearbox.
For me using + on the paddles 1st to 2nd is very short gear,and if im not hammering it,have to change very quickly.See if you can change high up the rev range,then back down etc.
Not ideal in a super duper ed30 on winter roads,wheel spin city!!!!

Chris.