All right, I'll take a shot at these.
NIC problem: I've been doing tech support for a bit more than a decade now, and NICs with Realtek chipsets are the ONLY NICs I've ever seen actually *fail* in service (barring lightning and/or other abuse). So you might have a dud NIC.
Dialup: besides Noble's dialup, you might have a look at this thread and try another dialup manager:
http://forums.contribs.org/index.php?topic=6118.msg21847#msg21847I have the other dialup manager installed from before I got broadband and it doesn't have the options you desire but it does offer you the ability simply to disable/enable dialing ... so you can have complete, if manual, control over your connection.
A note on your install error message reporting: you're not going to get far with a vague reference to an error message that ends in "or something." If you're installing your RPMs from a workstation using SSH connection, you should be able to copy the error message & paste it into a document or forum posting. Exact error messages tend to get exact results ... inexact error messages tend to get ignored.
Email: Messages will go out with the "reply-to" address you specify in your email client. If you wish to bypass the SME server for outgoing email, simply specify your ISP's SMTP server in your email client. Of course, your email client will then try to establish a connection to the Internet ...
Otherwise, you can have the SME box "hand off" all outgoing messages to your ISP from the "Other Email Settings" in Server Manager. This would probably be best, as the mailserver would hold your messages & keep looking for an Internet connection. When it finds one, i.e. when you dial up, off go your messages.