General

Error: Code 50100

Hi.
I've been doing these offers for 3 nx in the past but recently this error code keeps coming up.
When i click the 'earn 3 nx' button it leads to an error page stating the following:

Charge Account
You have reached this page through an error.
Return to the Charge NX page.(Code:50100)

Error

Please help me on this, if you have/had this error before and fixed it.
cheers.

or comment if you have any ideas.
thnx.