A plan has a participant in RMD status, and that participant received a distribution in early 2006. This would take care of his distribution requirement for 2006. He has now requested another distribution.
The plan provides for lump sum distributions only - no annuities or installments.
Can he receive another payment from his account now? This wouldn't count as his 2007 RMD - so I don't know if he can just request distributions at any time. His new request would still leave him with an account balance.

Thank you.

The participant can always take more then the minimum required distribution.

As to the second part of your question - I have to assume since you don't allow annuities that this is DC plan. Answer book states:

No. If, for any distribution calendar year, the amount distributed exceeds the minimum required, no credit will be given in subsequent calendar years for such excess distribution. [Treas. Reg. §1.401(a)(9)-5, Q&A-2]

Don't forget the most famous piece of advice:
What does the plan say?

I agree with pax - read the document and follow it. From what you've described, it doesn't sound like the participant is entitled to another (less than full) distribution this year.

If the plan allows lump sum only distributions, why does the individual still have an account? Once distributions started, the entire balance should have been distributed. Same if the particpant is an owner and still employed, although the plan may not be designed for that result for an owner.