After transfer from localhost to live server - tons of errors

I've recently transferred by Drupal website from my localhost to a live VPS. I have been met with a lot of errors that I have traced back to XMLsitemap. I am running D6.19 and my server has PHP 5.1.6.

On the status report page it displays two errors pertaining to the module:
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XML sitemap Last generated on 2011-02-28 10:19 (3 weeks 1 day ago).
The XML cached files are out of date and need to be regenerated. You can run cron manually to regenerate the sitemap files.
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*I am unable to run cron or access any admin page, I get a blank screen - not sure it is related
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XML sitemap cache directory Not found or not writable
The directory xmlsitemap was not found or is not writable by the server. See http://drupal.org/node/34025 for more information.
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I have enabled a couple XML site map modules prior to the transfer, they are:
XML sitemap custom
XML sitemap menu
XML sitemap taxonomy
XML sitemap (core)

The main error which appears on all admin pages is a large red box filled with errors that is pages long, below is an excerpt:
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user warning: Got a packet bigger than 'max_allowed_packet' bytes query: UPDATE cache_update SET data = 'a:80:{s:11:\"accountmenu\";a:23:{s:4:\"name\";s:11:\"accountmenu\";s:4:\"info\";a:5:{s:4:\"name\";s:12:\"Account menu\";s:7:\"version\";s:7:\"6.x-1.7\";s:7:\"project\";s:11:\"accountmenu\";s:9:\"datestamp\";s:10:\"1262239203\";s:16:\"_info_file_ctime\";i:1300717845;}s:9:\"datestamp\";s:10:\"1262239203\";s:8:\"includes\";a:1:{s:11:\"accountmenu\";s:12:\"Account menu\";}s:12:\"project_type\";s:6:\"module\";s:10:\"sub_themes\";a:0:{}s:11:\"base_themes\";a:0:{}s:16:\"existing_version\";s:7:\"6.x-1.7\";s:14:\"existing_major\";s:1:\"1\";s:12:\"install_type\";s:8:\"official\";s:5:\"title\";s:12:\"Account menu\";s:10:\"short_name\";s:11:\"accountmenu\";s:10:\"dc:creator\";s:9:\"mattyoung\";s:11:\"api_version\";s:3:\"6.x\";s:17:\"recommended_major\";s:1:\"1\";s:16:\"supported_majors\";s:1:\"1\";s:13:\"default_major\";s:1:\"1\";s:14:\"project_status\";s:9:\"published\";s:4:\"link\";s:37:\"http://drupal.org/project/accountmenu\";s:8:\"releases\";a:9:{s:7:\"6.x-1.7\";a:20:{s:4:\"name\";s:19:\"accountmenu 6.x-1.7\";s:7:\"version\";s:7:\"6.x-1.7\";s:3:\"tag\";s:7:\"6.x-1.7\";s:13:\"version_major\";s:1:\"1\";s:13:\"version_patch\";s:1:\"7\";s:6:\"status\";s:9:\"published\";s:12:\"release_link\";s:29:\"http://drupal.org/node/671376\";s:13:\"download_link\";s:63:\"http://ftp.drupal.org/files/projects/accountmenu-6.x-1.7.tar.gz\";s:4:\"date\";s:10:\"1262239203\";s:6:\"mdhash\";s:32:\"af74255baf521685390b67f18be0c352\";s:8:\"filesize\";s:5:\"11399\";s:5:\"files\";s:4:\"\n \";s:4:\"file\";s:10:\"\n \n \";s:3:\"url\";s:123:\"http://ftp.drupal.org/files/projects/accountmenu-6.x-1.7.tar.gzhttp://ft...\";s:12:\"archive_type\";s:9:\"tar.gzzip\";s:3:\"md5\";s:64:\"af74255baf521685390b67f18be0c352c3b9b0f31c2f223bc9c8db7b6fd7e01d\";s:4:\"size\";s:10:\"1139916990\";s:8:\"filedate\";s:20:\"12622392031293229433\";s:0:\"\";s:0:\"\";s:5:\"terms\";a:1:{s:12:\"Release type\";a:1:{i:0;s:9:\"Bug fixes\";}}}s:7:\"6.x-1.6\";a:20:{s:4:\"name\";s:19:\"accountmenu 6.x-1.6\";s:7:\"version\";s:7:\"6.x-1.6\";s:3:\"tag\";s:7:\"6.x-1.6\";s:13:\"version_major\";s:1:\"1\";s:13:\"version_patch\";s:1:\"6\";s:6:\"status\";s:9:\"published\";s:12:\"release_link\";s:29:\"http://drupal.org/node/592794\";s:13:\"download_link\";s:63:\"http://ftp.drupal.org/files/projects/accountmenu-6.x-1.6.tar.gz\";s:4:\"date\";s:10:\"1254371102\";s:6:\"mdhash\";s:32:\"31ed2901acfed4b341ee63ae0eb0065a\";s:8:\"filesize\";s:5:\"11226\";s:5:\"files\";s:4:\"\n \";s:4:\"file\";s:10:\"\n \n \";s:3:\"url\";s:123:
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After I disable all XML sitemap SUBmodules, the "big red" error disappears. Obviously, if I disable the core module the errors on the Status Report page also disappear.

Is this a bug or server configuration error? My max_allowed_packets is set to 256M, so it can't be too low plus my database is small <5M.

Tips appreciated