Drupal constantly crashing (MySQL server has gone away)

Hi there,
I'm trying to setup a Drupal+Ubercart shop to see if I can migrate our products from OSCommerce which is not doing the job we want (not sure whether it's a good idea though).
All went well until I tested a template, in theory made for websites with Ubercart. Firstly it required another base template, then a Skinr plugin. As it got more complicated, I gave up on the template and tried to go back to what I had previously. Result, site won't load anymore, all I get is this:

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 1050003 bytes) in C:\xampp\htdocs\cb-drupal\includes\common.inc on line 596

Warning: MySQL server has gone away query: UPDATE sessions SET uid = 1, cache = 0, hostname = '127.0.0.1', session = 'updates_remaining|a:0:{}node_overview_filter|a:0:{}imce_directory|s:6:\"images\";', timestamp = 1253070799 WHERE sid = 'f73d9e1c6e6e3c1e5568fc37a7c55868' in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: UPDATE users SET access = 1253070799 WHERE uid = 1 in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: DELETE FROM cache_menu WHERE cid LIKE 'links:navigation:%' in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: DELETE FROM cache_block WHERE expire != 0 AND expire < 1253070799 in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: DELETE FROM cache_page WHERE expire != 0 AND expire < 1253070799 in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: SELECT menu_name FROM menu_links WHERE expanded != 0 GROUP BY menu_name in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: UPDATE variable SET value = 'a:0:{}' WHERE name = 'menu_expanded' in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: DELETE FROM cache WHERE cid = 'variables' in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

Warning: MySQL server has gone away query: DELETE FROM cache_menu WHERE cid LIKE 'links:admin_menu:%' in C:\xampp\htdocs\cb-drupal\includes\database.mysqli.inc on line 128

INFO:

• System: Windows XP
• Localhost, XAMPP Win32 1.7.1
• Drupal 6.13

Memory doesn't seem to be a big issue, but this "gone away" SQL message is killing me.
Thoughs anyone?

Thanks heaps,
Perroud