You will receive "Putty Command Line Error" as below if your are using GNS3 and later version.
To overcome this error, just go and download Putty.exe that provide from below link.
After that , overwrite the Putty.exe in your pre-installed Putty.exe
Download Putty for GNS3
Once download and overwrite the Putty.exe, you may try to console Router/Switch/Firewall in GNS3.
If you want to know about for that, read details at http://forum.gns3.net/topic5016.html
May you all be happy.
(Be knowledgeable, pass it on then)