Fix Magento CE1.7 - error generating invoice

Avg Bid (USD)
$8 / hr
Project Budget (USD)
$2 - $8 / hr

Project Description:
After an order is placed in Magento , I am unable to generate invoice. It shows a big error magento page which says:
There has been an error processing your request.
Cannot get order instance.
and lots of urls below.
This happens when I click on the invoice button in the order detail page in backend when the order status is processing/pending payment.

Kindly help me resolve the issue. This is really an urgent project. If you can resolve it in no time, I have lots of magento projects for you.

Thank you.

Hours of work: Unspecified Project Duration: < 1 week Skills required:
Hire MonsonKings
Project posted by:
MonsonKings India
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$9 / hr
Hours: 5 hr/ week
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Hours: 40 hr/ week
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Hours: 40 hr/ week