missing buttons after copied instance

Hello,

we have a working biserver-ce 5.0.1 install on one machine ("A").

When we copy this installation to another machine ("B"), it does work, but some buttons, i.e. some functionality in some places is missing.
A good example is the "German Langauge Pack installer" (also for the French).
When I select the link, I get the box with the installer info, however the "Install" button is only there on machine A, not on machine B.
To make sure, we copied back the complete biserver-ce from B to A. Still, button is there on A, not on B.

Now, what except the biserver-ce could be different.
- identical java install on both machines
- users have admin rights, obviously. pentaho user names are identical.
- different run users / install owners. Is the unix user cached/saved/written somewhere ?
- database - we did start out with identical databases.
- unix install - are there some libraries required on the unix side ?

pentaho.log shows identical JSON for language pack installer.

We dug into that installer page - the DOM is identical to the buttonInstallObj DIV - but on machine B the DOM nodes does not have a BUTTON child.

Any pointers what could be causing this behaviour is greatly appreciated.

Thanks, Tom.