When I use Characters with Groove selection mainly all of Warusaki3's and kod's. The first match I start, it automatically selects a groove for me....... well to be more clear no groove selection ever takes place. Theres nothing wrong with gameplay for warusaki3's stuff but for KOD's his characters seem to be stuck in a running position until someone attacks it.
Have you tried to install some tag patch or another program or files which made you modify the character ?Try using a clean winmugen and insert the characters in them to see if they work correctly (no reason they shouldn't)
this only occurs for the first match up when i first start mugen... after that they work perfectly fine.