Email from a worksheet

I have this code to generate an email message and send it.

Please Login or Register  to view this content.

But this seems to work intermittently. 7 Emails went through OK. 5 Never made it. I even broke up the message so there were two complete emails being generated and sent. I thought the bcc might have been causing some problem. Is there a better way to do this? I got this code (almost an exact copy) from a web site. There is nothing on that site to suggest there would be a problem or to help identify this problem.