[TYPO3-dam] Strange install problem

[Oliver Wand]

Dear all,

trying to install DAM on a fresh TYPO3 4.0 on FC4 with PHP5 I´m running 
into a strange behaviour here:

Whenever I click the "+" to install the necessary options are asked, 
after clicking "Update" I´m returned to the Ext-Manager-List-View and 
DAM extension is still uninstalled.

No error message occurs.

Can anyone help me out here? :-)

TIA,

Oliver