fix <installconditions> validation in PHP 5.0.5
fix <installconditions> validation in PHP 5.0.5

# ANOTHER BC break in PHP?!  isset() does not work
# for array indices any longer if the var isn't an array


git-svn-id: 4b064e69dc630d28214c1e1442d27300cccf8e9a@197395 c90b9560-bf6c-de11-be94-00142212c4b1

DQNEO/PEAR_Exception