As per the Apache documentation (http://httpd.apache.org/docs/2.4/mod/core.html#servername) the ServerName directive may accept a port ([:port] as noted in the syntax). But the script wampserver.lib.php does not allow optional ports and as a consequence port-based virtual hosting may fail validation (in my case I wanted to set up 2 VH: localhost:80 and localhost:90 because I'm running Wamp locally and didn't want to declare fake names in etc/hosts): I couldn't launch my virtual hosts from the Wamp menu.
The fix is as follows: add the following line after the #287:
(:[0-9]+)? # Port is optional
Wampserver 3.0.5 does not support the various ports for VirtualHost - just the same port for all VirtualHost - so add a port to the ServerName is not allowed and it will not be supported in the future.
However, VirtualHost by local IP are supported.
Using VirtualHost and hosts file is not using "fake names"; is use that Apache and the operating system provides.
Note: It was by chance that I came here. As indicated in the installation procedure of Wampserver, the "support" is provided ONLY by the forums: http://forum.wampserver.com/index.php