That's because developer.apple.com no longer supports older TLS and SSL protocols - it only supports TLS 1.2 (see https://www.ssllabs.com/ssltest/analyze.html?d=developer.apple.com). Older Safari versions (before version 7) do not support TLS 1.2 (see https://en.wikipedia.org/wiki/Template:TLS/SSL_support_history_of_web_browsers) .
You could try installing Firefox or another browser in the VM tohoping they have updated certificate stores and will negotiate a secure connection for access theto that site.