Issues with Quartus II web edition installation

Hello,

I tried to install the quartus ii web edition (32 bit) and had been successful in installing that I hope.

I downloaded the windows executable from the webpage: https://www.altera.com/download/archives/arc-index.jsp
Tried to install the June 2012, 12.0 SP2 web edition. It installed four folders in my machine in the folder:
C:\altera\12.0sp2\ , the folders are installer, ip, nios2eds and quartus respectively.

Then I wanted to install ModelSim-Altera Edition 10.0 d and downloaded the respective executable (12.0 SP2) and tried to launch it.
It gave me a message like 'Apply Service Pack into the Selected Installation Directory' in the 3rd step for which I selected the
'C:\altera\12.0sp2' folder, where I previously installed the quartus.
However when I click 'Next' button, I get an error message from Altera Installer 'You must install the service pack in the same directory
as an existing Quartus II software installation. Specify the directory for the existing installation' [!!!!!]

I thought I have specified the proper directory here. I am having no clues, please help me out. Really appreciate for any help.

[I have same issue when I tried to install the NIOS II EDS (12.0 SP2), the same error message]


Thank You,
Akhil Kalathungal