netware security message

hi friends,
i am facing a problem in login in to netwaree server 5.1.
first i give u the detail of the netwaork.
i have netware 5.1 as a server and windows 2000 as a client. i have installed novell client 32 in windows 2000 pro. till now it was working ok but now i am getting a error when i am login in to netware server the error messgagee was as follows.

netware security message

internal error 0xffffffdsf occured try again if error again restart your workstation and try again if the error perrists, contact your netwotk administrator.

i had tried all the think which the error has suggest. i had ever uninstalled and reinstalled the client software but the problem presist.

can u tell me why the error occured and what is the solution.