thanks alex and dave,
well i didn't followed any books cos it didn't let me go anywhere. i did a new thing.
put all the files in the cgi-bin directory of the Apache directory in Windows 98.
php.ini, php.exe, all the required dlls. all the extensions and didn't change the extension_dir line in the php.ini file and is working fine. but i didn't uncomented the dll path in the php.ini file.
maybe the php.ini file is not getting the path of the dlls. thus put them all in the same directory and it works well. thanks for all the help.
a bit of research to do in GD library since it is up and running now
cheers
kalyan