Hi Bellyup,
Can you be a little clearer. Where is the website - on SBS, SME or external ? What mode is your SME server in gateway / standalone ? If gateway have you modified the firewall rules ? What's a card reader login ? What ports are you trying to access ?
As for differences between SBS and SME, how long have you got ? They're radically different from a nuts-and-bolts point of view.
Damian