Why does the Mac OS X firewall dialog recurringly pop-up and disappear by itself (without letting me respond) under Snow Leopard

From time to time, I'll be on my Macbook using a program that accesses the network – whether Firefox, or Sony's Reader Library – really, it seems like it could happen with any program that accesses the network – and for no reason that I can discern so far (that is, it happens intermittently) the OS X firewall dialog pops up to ask me the question:

[OS X firewall dialog] Do you want the application "Reader Library.app"
to accept incoming network
connections? Clicking Deny may limit
the application's behavior. This
setting can be changed in the Firewall
pane of Security preferences. [Deny] [Allow]

Except it doesn't actually let me click anything before it disappears! That is:

• the dialog pops up, …
• then goes away by itself a second later,
• then pops up again, …
• then goes away by itself a second later,
• etc.

It happens a few times before stopping. It wouldn't be so maddening to be interrupted if I could just be allowed to click "Allow" and make the darn thing go away for good.

In Security preferences I have the firewall turned "On", and I would like to keep it that way.

Has anybody seen this problem, found the source, and figured out a solution or workaround?

Thank you.

UPDATE: I had found these message threads confirming the issue: MacRumors.com – Firewall application exceptions: dialog disappears strangely, and Apple – Support – Discussions – Annoying Firewall Allow / Deny Dialog. As of March 27th, 2010, there's still no solution reported at either of those links.