Would you please help me with my confusion about GPL, here is my case :

I have been testing Pentaho BI server community edition, and after reading the licensing terms I found out that the community edition is under GPLv2.

As we all know the server is intended to host different types of files and applications (like reports, olap cubes,etc...)

My question is : are we allowed to sell applications that run on the GPLv2 server ? (we will maybe modify the server source code a bit but we won't charge it to our clients. thus the modified GPL server will be just an execution environment or a container for the reports and applications that we intend to sell) ?

this suggests that our clients must install the GPL v2 edition first and then buy from us the applications that work on it but not their source code.