Honest, we have fixed it this time!
After months of work, new ideas and starting again we believe we have the fixed stability issues with Burf.com. No more will you do a search, wait 10 seconds and be returned an error. The answer was down to clustering of the search index into 37 different tables to spread the load. This has resulted in a small decrease in speed in indexing sites and producing search results however will allow for a greater uptime and a much larger index!