Spurious(?) error messages in Scala Interprter

[Pillsy]

Hello, all,

I recently installed Scala IDE 2.0.0 beta 9 (for Scala 2.8.2) on top
of Eclipse 3.7.0, running on Mac OS X 10.6.8. The installation seems
to be working correctly in terms of the compiler and debugger.
However, when I launch the interpreter (with or without a selection),
I usually get an error message after the first evaluation, and then
things appear to stop evaluating entirely, with no sign of results. A
typical session goes something like this

> 1+1

res0: Int = 2
<script>:3: error: value tools is not a member of package scala
var value: scala.tools.nsc.InterpreterSettings = _
<script>:4: error: value tools is not a member of package scala
def set(x: Any) = value =
x.asInstanceOf[scala.tools.nsc.InterpreterSettings]
^

> 1+1

I would expect something like "res1: Int = 2", but nothing at all
appears. No command I enter after the first produces any output.
Evidently some package or file isn't being loaded correctly, but I'm
not sure where to begin so that the interpreter can find it.

Thanks,
Pillsy