There are several time issues to be aware of in group long term disability claims governed by ERISA.
1. You must give timely notice of your claim and then follow up with timely proof of your claim.
2. Generally, if your claim is denied you have 180 days to "appeal" that denial. That "appeal" goes right back to the insurance company that decided you weren't entitled to benefits in the first place!
3. If you do have to file suit, you CAN file your case in STATE court but it will be removed (transferred) to Federal Court in all likliehood. There is NO ERISA statute of limitations. Courts generally follow the whatever state statute of limitations applies to written contracts.
HOWEVER, be warned that buried in your employer's insurance plan may be a hidden statute of limitations that is much shorter (as short as 180 days I have seen!). You must read your plan from front to back, and use a magnifying glass if necessary.