Thanks for the response and help, I tried as you suggested but it didn’t work for me. After reading through a few threads I found that this issue has been reported…
In addition, I found a manual fix that worked for my site (note: depending on the number of attributes this could be tedious).
1. For each searchable attribute, under front end properties, change the “Use in quick search” drop down menu to No.
2. After this field has been disabled for all attributes, go to system, cache management, and rebuild the search index (this should now be possible and not give the .../Abstract.php on line 351 error).
3. Now go back and change the “Use in quick search” drop down menu to Yes for each attribute.
4. Rebuild the search index again (it should now work without error).