Dear Ankas,
Looks like your micro is hit by RFI/EMI

1. Are you using mechanical relays to switch AC Servos?
2. Do you optocouplers in betwwen ULN2003, and micro port pin?
3. Are you using separate supplies for relay driving and micro or same supply?
4. Are you using snubbers across the the relay O/P.

*.I would preffer to use SSR [ Solid State Relays ]. with snubbers across O/P. and separate supply for micro and SSR.

In case you want to do it with mechanical relay take following precautions.
1. Use optocouplers in betwen ULN2003 and micro.
2. Use separate supplies for driving relays and micro.
3. Use snubbers across the O/P od relay.

have a look at http://www.8052.com/faq.phtml?FAQ=84

Bye