*sigh*. Fortunately, I've never had the problem you have had with the blocking toads, but so many of our posters have. Normally, I would never advocate violence against peaceful non-opponents, but...
if you've got it, Meteor their butts out of the tunnel!!!!
that is, if you have Meteor (4th level Stone spell). Elemental Blast may work, but if even one survives, they'll call out and you're the "sister of bad news" down there among the now-hostile toads...which basically means you can't kill the evils at the Sacred Toadem (Shinwiki won't open the trap door for you.)
If you don't have a high enough spell level, you may want to go back to the Crypt and get your characters up in level far enough until your wizard has one of the above spells.
Other options: Stack crates in the water outside and use them to "jump" to the other platform, and enter Toad Village from that side...
For advanced players with the Vanish spell, simply "Vanish" the toads to another location. Or, vanish yourself past them.
Hope this helps.
-Sazerac
P.S. Never heard of the "pit" thing...sounds like a bug.
[This message has been edited by Sazerac (edited 03-16-2001).]