I am having funny issue and need some advise, pls?

We have a school policy to change password periodically.
When a user's password has expired, the user visits IT helpdesk to reset the password.

When IT Administrator updates the password for the user from iManager it takes more than a few hours or max 1 day.
On the other hand, it works straight away from ConsoleOne.

Furthermore, there is another funny issue about user creation.
When a new user account is created from ConsoleOne, the user can login on the first time, it fails the 2nd logon forever.
When a new user account is created on iManager, it works perfectly.

We have switched to iManager since Jan 2010, and we found this problem recently. But because of this issue, we have back to ConsoleOne only for password change.

I think there is a major different about both user creation and password job between iManager and ConsoleOne that has given me a headache.

This is what we have been doing to avoid these problems.
1. Create a user account from iManager
2. Then, update the password from ConsoleOne
3. No problem now but why we need 2.?

Could you give me an advise, pls?

Servers: Several OESSP2 on SLES10SP3 and A few NetWare6.5SP8
Client: Windows XP SP3 with Novell Client 4.91 SP5
ConsoleOne: 1.3.6h
iManager: 2.7.3 on OES2SP2 on SLES10SP3