It seems that the cPanel did not communicate the 5.2 version to the proper files as your php still reflected 5.3.
I added a line to your .htaccess file and the php now reflects as 5.2.
You should now be able to install the software. Please let us know if you need any further assistance.
Yes, if you're having the same problem, then it may be that the program is not recognizing the php version, and the stated fix (by Scott M.) should explicitly state the version. Here's the code he added to the .htaccess file:
# Use PHP52 as default
AddHandler application/x-httpd-php52 .php