Unfortunately the trial ended soon. My first step after running the installer was to try to install some PEAR packages using go-pear, which does not work. Problem reports and a workaround can be found in the Zend forum.
PS: The sad part is, that this problem was already reported with the beta version of Zend Core. But apparently PEAR is not that important to Zend, so this error still exists in the final version as well.