Hi,
If you are installing .Net Framework 1.1 on Windows 64 bit system then you will need to follow the below steps after completion of the installation:
1- From the Start menu select Run then press the Enter key
2- In the "Open" edit field enter the following command:
cscript %SystemDrive%\inetpub\AdminScripts\adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 1
3- Press the Enter key
Regards,