Troubleshooting ocart help needed

I am having an issue with confirming transactions. When trying to complete the transaction i get this message:
The transaction was not sent to the host because of a duplicate order id
Can anyone help me with this. I am willing to pay, just need it resolved!

Hi,

i am a developer working on php based web development. i am working on opencart since last 8 months and being experienced in cakephp i am very familiar with the MVC pattern opencart follows.

if you still need a opencart developer i'll love to work with you. my Gtalk id is nitinrai321.

please let me know

Thanks
Nitin