Saving Mashup Problems

Hi all, I am trying to save a Mashup and I am getting the following error and not sure how to resolve this problem:

Sorry, but your project maynot have been saved successfully due to an internal server error (invalid token)

Can anyone explain what this means and how I can resolve this issue, so I can save my Mashup?

Thanks for any help you can offer :-)

...Ry

[495 byte] By [Ryanph] at [2008-2-4]