Soap Error: Bad Request on fresh install

[mister-wolf]

Hello,
just made a fresh install of Ispconfig 3.0.5.4p5 and Roundcube 1.0.5 on Ubuntu 14.04.1 LTS.
I followed your installation instruction (manual) and doublechecked everything.

Unfortunately I get "Soap Error: Bad Request" as soon as I click on any plugin in Account section.
Same error if I try to change passsword or add a forwarding address.

Can you give me any help on debugging this issue?
I see no errors in apache error_log.

I run roundcube under http.
This is the plugin config row:
$rcmail_config['plugins'] = array("jqueryui","ispconfig3_account", "ispconfig3_autoreply", "ispconfig3_pass", "ispconfig3_spam", "ispconfig3_fetchmail", "ispconfig3_filter", "is
pconfig3_forward", "ispconfig3_wblist");

jquery is 1.9.1

[mister-wolf]

see error screenshot below

[mister-wolf]

forget about that.
uninstalling and reinstalling soap did the trick.