Scala sometimes fails to load a jar

Hello all,

I've been using scala fairly heavily and often just write short one
object programs that tie together a number of classes defined in a
java package i've been working with, as if my scala code is the main
for the java tools.  I tend to run things without compiling with
simple commands like:

    scala -cp sspace-lib.jar MyScalaProg.scala args_here

And that works for the most part, except on certain occasions where
scala, for reasons unknown, fails to load the associated jar, sspace-
lib.jar.  Sometimes I can solve this by running scala from where the
jar is located, othertimes it's the exact opposite.  Here's some
sample runs to clarify:

$ scala -cp bin/sspace-lib.jar DTest.scala

    /home/stevens/devel/S-Space/DTest.scala:32: error: not found:
value log
        a.zip(b).map(v=>if (v._1 == 0d) 0.0 else v._1 * log(v._1/
(v._2+eps))).sum

Everything looks as expected, I forgot to import log but otherwise it
recognizes my java based imports

$ cd bin
$ scala -cp sspace-lib.jar ../DTest.scala

  /home/stevens/devel/S-Space/bin/../DTest.scala:1: error: not found:
object edu
  import edu.ucla.sspace.vector.CompactSparseVector
         ^
  /home/stevens/devel/S-Space/bin/../DTest.scala:2: error: not found:
object edu
  import edu.ucla.sspace.common.Similarity
         ^
  /home/stevens/devel/S-Space/bin/../DTest.scala:32: error: not found:
value log
          a.zip(b).map(v=>if (v._1 == 0d) 0.0 else v._1 * log(v._1/
(v._2+eps))).sum
                                                        ^
  three errors found

Everything is not fine, my two imports using the sspace-lib.jar are
not recognized when I try to run scala from the jar's local
directory.

If i try to compile, things seem to work as normal, and I can
similarly load the jar into the interpreter from any directory.  It
just seems to be that this particular use case *sometimes* doesn't
work.  It's very finicky.

I can't really imagine why or how scala would fail to load up a jar
based on the current running directory.  Has anyone else run into
similar problems?  I've had this occur on two separate Redhat linux
machines and a Ubuntu laptop.  All systems are running Java 6 with a
fairly recent sun jvm.  I'm also using Scala version 2.9.1.final.