Hi friends,i really met a big problem for my site:
It worked perfectly on my zencart 1.51 site,but with the increase of the products,i could not open the main page and admin page right now,it reminds me error message,when i checked the log file,i found the following information:

[02-Aug-2013 10:31:14] PHP Fatal error: 1153:Got a packet bigger than 'max_allowed_packet' bytes :: INSERT INTO seo_cache (cache_id, cache_language_id, cache_name, cache_data, cache_global, cache_gzip, cache_method, cache_date, cache_expires) VALUES ('ca34fbe5f9a075091ad59abf02c259a7', '1', 'seo_urls_v2_products'

The problem now is i could not change the max_allowed_packet bytes,even i changed it,the problem will happen again with the increase of the products,anymore have cure on this, i really appreciate your help,thanks