Error upgrading from 8.4 to 8.6

[mysticav]

Server Info:

Plesk: 8.4
Distro: Fedora 6
PHP: 5.2.6
MySQL: 5.0.27

Error Message:

ERROR: PleskMainDBException
Up LevelUp Level
MySQL query failed: MySQL server has gone away

0: /usr/local/psa/admin/plib/common_func.php3:214
db_query(string 'SELECT id, type, url, priority, enabled, auth_required, login, password FROM ai_vendor_sources')
1: /usr/local/psa/admin/plib/autoinstaller/AutoInstallerVendorSource.php:136
AutoInstallerVendorSource::getVendorSources()
2: /usr/local/psa/admin/plib/autoinstaller/AutoInstallerManager.php:209
AutoInstallerManager->install(string 'PLESK_8_6_0', array, boolean false, string 'support@xxxxx.com', boolean true)
3: /usr/local/psa/admin/htdocs/server/autoinstaller_install.php:101