The reason for doing telnet it to count the presence of valid application which listens to a certain port.

Does that application speak the telnet protocol (RFC 854) or do you just need a connect scan? For the latter, get rid of Net::Telnet and use IO::Socket instead. I think you are confused by the fact that many telnet client implementations automatically and silently switch to a more or less raw mode when they can connect to a port, but cannot negociate a telnet connection. This happens for example when you telnet to an HTTP or SMTP server.

The reason to scan blocks of IP is because its not clear which ip in network is available(up and on) i.e basically simplify the search.

Use nmap for that. Tell nmap to scan a list of IP addresses or IP ranges from a file with a simple TCP connect scan on the application's TCP port. Leave the ping scan enabled to sort out machines that are down, disable the ping scan if the machines are stupidly configured not to respond to ping requests. nmap will deliver you a list of all hosts that are in the list of IPs and can be connected on the application port.

Alexander