Can not boot - error message

Hi,
I have been using SARDU for over a year now and are very happy with it.
Recently I updated my SARDU install on my Imation Nano Pro 4 GiB USB thumb drive.
The SARDU version is 2.0.3. I tried both versions available in SARDU for Syslinux.
Although I never had a boot error before now when I try to boot from it I get a black screen with in the top left the text "Can not boot".
Any idea what may cause this and how to solve it ?
Best wishes,
William
I have been using SARDU for over a year now and are very happy with it.
Recently I updated my SARDU install on my Imation Nano Pro 4 GiB USB thumb drive.
The SARDU version is 2.0.3. I tried both versions available in SARDU for Syslinux.
Although I never had a boot error before now when I try to boot from it I get a black screen with in the top left the text "Can not boot".
Any idea what may cause this and how to solve it ?
Best wishes,
William