Authentication Manager 8.1 SP1 Web Tier installation fails with:
Prerequisites Check Unsucessful 
Unsuccessful: The system prerequisites are not met. 
The installer has detected that the system does not meet the prereqisites for installation. Resolve 
each message shown in the details section, and then click Next. To ignore the message and proceed 
with the installation, select Ignore and Continue. 
"The TCP port 7030 cannot be bound for an unknown reason"
"The TCP port 7036 cannot be bound for an unknown reason"
"The TCP port 443 cannot be bound for an unknown reason"
Ignore and Continue

Name resolution is incorrect, so the ports used in Web Tier, 443, 7030 and 7036 cannot be bound to the wrong server that is returned from the incorrect name resolution.

Fix name resolution, either in DNS Domain Name Services or in the local /etc/hosts file
This appears to be caused by the correct server name being bound to the wrong IP address in the local Web Tier ../etc/hosts file

edit ../etc/hosts

Originally seen in single case, 00494056 back in May 2014 and case 00633636 notes that the code you can see these messages are from PortBinding Exception, and this class belongs to install prep package.

private void handlePortBindingExceptions(IOException e, Integer currentPortToCheck, String portType)
{
if (e.getMessage().contains("Permission denied")) {
this.failureMessages.add("The " + portType + " port " + currentPortToCheck + " cannot be bound because you do not have permission.");
} else if (e.getMessage().contains("Address already in use")) {
this.failureMessages.add("The " + portType + " port " + currentPortToCheck + " cannot be bound because it is already in use.");
} else {
this.failureMessages.add("The " + portType + " port " + currentPortToCheck + " cannot be bound for an unknown reason.");
}
}