Hi Kritika,
Difficult to be sure without further information such as the exact error message you're seeing...
But it seems you are compiling everything yourself? In that case you will also need to compile and install the powertac-core package, before you can compile and install the server and sample-broker packages:
https://github.com/powertac/powertac-core/Not doing that would indeed lead to not being able to resolve the parent POM (which resides in powertac-core).
Incidentally, compiling from source is fine of course, but for the tournaments it might be slightly safer to instead simply use the RELEASE (rather than the SNAPSHOT) versions.
Hope this helps,
Erik