Unfortunately, this seems to be an issue with the software itself. (This in fact affects many sites using the same software.)
The
solution would be to downgrade to PHP 5.3 but that does not seem to be an option here.
So, I guess the software would have to be considered not supported.
Edit: you can use the following information to help out if you really wish to get this working, though it might be seen as complex if you do not have sufficient experience with the PHP programming language (or any skills required to identify where things should go and what needs changing exactly)...
http://forum.phpvms.net/topic/20629-most-common-fixes-phpvms-installation/page__hl__$_files