I have been running Adobe Premiere 6.5 for 3 years now with a Matrox RTX 100 capture card with much success. Recently I went to use Premiere only to get the Matrox digisnif error message. At this point Adobe freezes and eventually shuts down. I have tried taking the Matrox tools out and reinstalling them and that works for a short while but, I eventually end up at the same spot. I am very frustrated because I have a small company and I can not afford to have the system down.
sounds like either your RTX100 card is dying or some other component in your system is. HEAT could be the problem.
A working stable system should not stop working. I would remove the card, blow on the contacts and re-seat it firmly. check for excess dust or other things that could cause your system to run hot. HEAT is the enemy.