Problems installing ISE 6.2 under Linux

Hi, I'm trying to install the ISE 6.2 update under Linux. My current version is 6.1 with no updates, straight from the CDs.

I get the following message : "Xilinx Service Pack 6.2.01i Setup cannot be installed over Xilinx install versions older than 6.2i."

Since I have 6.1, this shouldn't happen.

I found the following in the answer database :

but it doesn't really help as it should be already fixed and, besides, the $$XILINX variable seems to be set ok.

I tried the obvious things mentioned in other answers like killing the wind processes and deleting .windu*, to no avail.

I'm stuck, can anyone help ? Maybe I need to install other 6.1 updates before 6.2?

Thanks,

Arthur