Google Sitemap problems: easy Replacement?

Hi,
well….. I still try to get the hang of SEO… since this question.
I am running a site with a google sitemap (its an addon from a CMS system…which produces that map).. I have an account at googlesitemaps and entered the googlesitemap address there. Everithing worked just fine for the last 5 month (got great stats (e.g. keywords, ranking….) and now suddenly (it was probably me) google gives me an error message when triing to access the map.

I try to fix it myself but no luck. Now, if I decide to cancell this account, replace the sitemap, put a new sirtemap (including a google search box) on my site… open a new account etc.
will it just remember the old settings of the site (stats, ranking, keywords, index, analysis…..) or does it strart from scratch? Will this affect my SEO in any negative way??

Wow.. that was a long question, but nevertheless I hope you guys can help me out

Cheers,
Cosmoglobe