Couldn't find starting point in this job - only on Linux

Hi,
since a few weeks I am working from time to time with PDI Release 4.4.0 creating some transformations.

It's all working fine on my Win7 Desktop.
I can create Jobs and let them run as Windows batches via kitchen.bat.

But, finally, the whole stuff has to run on a Linux server when it goes Beta or production.

So I tried to bring a very small Job with Start, Transformation and Success to my little Linux machine.
The transformation has Get System Info, Add Constants, Concat Fields and writes IP and a little text to a mySql table.
As already said, it's running out of Spoon AND as a batch on the Windows machine.

I unzipped pdi-ce-4.4.0-stable.zip on the Ubuntu 12.04.1 machine, copied the .kjb and .ktr to the data-integration directory and started the kitchen.sh.
This is what happened (debug log):
2013/05/28 17:04:58 - Kitchen - Logging is at level : Debugging
2013/05/28 17:04:58 - Kitchen - Kettle version 4.4.0-stable, build 17588, build date : 2012-11-21 16.02.21
2013/05/28 17:04:58 - Kitchen - Start of run.
2013/05/28 17:04:58 - Kitchen - Allocate new job.
2013/05/28 17:04:58 - Kitchen - Parsing command line options.
2013/05/28 17:04:58 - Start of job execution
2013/05/28 17:04:58 - ERROR (version 4.4.0-stable, build 17588 from 2012-11-21 16.02.21 by buildguy) : A serious error occurred during job execution: org.pentaho.di.core.exception.KettleJobException:
2013/05/28 17:04:58 - ERROR (version 4.4.0-stable, build 17588 from 2012-11-21 16.02.21 by buildguy) : Couldn't find starting point in this job.


So, at least kitchen seams to start.
But obviously I'm missing a crucial part.
Can it be the result of a wrong java version? (Open JDK, 1.6.0_27)

Any other ideas?

Best regards,
Dieter