The F1 ( Online Help) is not working in SAP R/3 Enterprise Edition

Try this and see if it works, this had worked for me. Make the entries in T-code SR13, point it to the box where the help files are installed.

Thanks for the information .
But  can you please let me know what type of entries i need to do in T-code SR13 .
Also in which layer i should do whether it is Development , Quality or Production .
 
please let me know in more detail .
thanks in advance

 We need to do this in all the systems you have. This steps might help you :   1) Click on the HtmlHelpFile 2) Enter Help as the variant 3) Platform as either Unix or Windows NT depending on you OS 4) IWBHELP in the Area tab 5) In the path speciy where the help files are located 6) Language as EN 7) then click on the default button. Just give this a try and hopefully it should work.

Thanks a lot it worked.