configuring windows 7 firewall for working with aspinet.dll

hi in windows Xp and windows vista the opensurce dll [login to view URL] is working fine in windows 7 professional ( i tryed with 2 pc) it is blocked from windows firewall. if i disable the firewall the dll work. i tryed to open the port tcp 21 in inbound connection, but nothing. how to solve this, without open too much the firewall? in attachment the dll and asp code to make test.