Hi the problem come from the ksoap you use.

It's the full for J2SE

Or blackberry is on J2ME.

SourceForge.net: Files

and take the ksoap2-j2me-core-2.1.2.jar and don't forget to preverify it

preverify -classpath "C:\Program Files\Research In Motion\BlackBerry JDE 4.3.0\lib\net_rim_api.jar" Path_where_the_jar_is_located\ksoap2-j2me-core-2.1.2.jar

And recover the jar in the output folder located in C:\Program Files\Research In Motion\BlackBerry JDE 4.3.0\bin.

With this all should be ok