echo "< a href='getprod.php?=prodid=".$prodnum.'">";
echo"THUMBNAIL<br>image</a>
If you use an editor with syntax highlighting, the error in that row should become apparent.
When you post php code here, wrap it in php bbcode tags. HTML code goes in html tags and other code go in code tags. See the blue part towards the end of this line? PHP string literals is supposed to be red, not blue. You screwed up the sequence of your quotes
echo "< a href='getprod.php?=prodid=".$prodnum.'">";