Problem about expanding folder

I am currently installing business package according to portal best practice.

Most of functionalities seems to be fine but I face a problem about expanding folders

for some role such as MM Master. For the same role, those worksets w/o folder

(directly call R/3 transaction) are working fine.

When expanding folders, we always got result showing "Loading..." and nothing

is shown for very long time.

Kindly advise how to resolve or further investigate such issue.

Note: Normal folder expanding of standard admin folder does not have such problem.