Unable to install gantry

I have downloaded rt_gantry_j15-3.1.20-bundle.zip  (also tried with previous 
version 19)

I try to install by uploading and install the zip file.  Have also tried FTP 
uploading the unzipped file to my tmp dir where Joomla resides.  Both methods 
give the same results.  I have re-installed Joomla 2.5 twice to start from 
scratch but am still getting the problem.

I have not had any problems installing other extensions in the past.  This is 
the first time.

The first couple of times it appeared to be installed and two entries for 
gantry showed up in Manage Extensions.  I believe I got one green bar and two 
yellow bars saying that the components had been installed, however gantry could 
not be found in templates.

Now I get errors saying that there is a file in components and admin, so I have 
removed them (FTP) and now I am getting

Fatal error: Cannot make static method JInstaller::getInstance() non static in 
class RokInstaller in /my 
website/cms/administrator/components/com_gantrytemplateforjoomlabundle/installer
/lib/RokInstaller.php on line 227

I am on Linux, Joomla 2.5, gantry 3.1.20

Any help would be appreciated.

Original issue reported on code.google.com by ma3ryp@gmail.com on 2 Apr 2012 at 6:18

austgl / gantry-framework

Unable to install gantry #32