I have had to change the quotes around the address from single quotes to double quotes a couple of times.
Here is what I get from the embed link:
<a href='http://scratch.mit.edu/projects/connors934/178774'><img src='http://scratch.mit.edu/static/projects/connors934/178774_med.png' width='425' height='319' alt='Scratch Project'></a>
Here is what works
<a href="http://scratch.mit.edu/projects/connors934/178774"><img src="http://scratch.mit.edu/static/projects/connors934/178774_med.png" width='425' height='319' alt='Scratch Project'></a>
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