Can anybody please tell me what are the pre-requisites to understand the suffix trees.
I am learning suffix tree from this:
http://www.allisons.org/ll/AlgDS/Tree/Suffix/
I am not very good at algorithms and I couldnt understand how suffix trees are made.
Please help me!

Perhaps you should try to learn about trees in general. Most people start with linked lists to get a feel for how linked data structures work, then they move on to binary search trees, and then to graphs. Generally if you understand binary search trees, it's not a great leap to prefix or suffix trees.

Another point of research might be searching theory. If you understand several of the common search algorithms, you can more easily digest the details of a suffix tree as the concepts will be more familiar.

Thanx for the help.
Actually I have learned lists , stacks and queues.I have to learn trees and graphs and searching theory,I am using Cormen.Do I also need to study Red-Black Trees and AVL trees to understand suffix trees??