Holy crap, your site is like 3 times bussier than mine, but my alexa ranking is around 5 times smaller!
www.alchemist-team.net Why could that be?
- Traffic Rank for cryo-laboratory.com: 3,445174143,448 (
2,657,100)
- Speed: 74Slo100w 68 70 80(72% of 40sites are 43fa34ster), Avg8857 9564Load T80im2e:32 451430 27 3.75 44 Second8756s5415 54 309835

Perhaps its because its very slow for the Alexa crawl bot? Accually, yes it is.. if you goto your traffic page, it says Unkown for the last few days and such, the reason for this is Alexa cannot get into your site! I suggest you try the following in order:
1. Remove any robots.txt you may have
2. Check and remove .htaccess if you donot need it like most people
3. Get Zoints SEO and follow a tutorial or guide on how to make your vBulletin bot friendly!
anywho, best of luck mate!