This is assuming you have Gimp-2.6.11 installed and you have installed the latest help files into it.
Setting up help for Gimp-2.7 (Parthas Portable)
Download the files for
help browser that MareroQ provided.
You need these dll files from Gimp-2.6.11 bin folder.Copy them to the Gimp-2.7/bin folder.
libxml2.dll
iconv.dll
Copy the entire help folder from gimp-2.0/share/gimp/2.0/ folder to the Gimp-2.7/share/gimp/2.0 folder
THE DOWNLOADED ZIP FILECopy the libgtkhtml-2.0.dll to the Gimp-2.7/bin folder.
Copy the help.exe file to your gimp-2.7.4/.gimp-2.7/plug-ins folder (this is the USER add on resources plug-ins folder)
Restart Gimp-2.7 (i used Parthas portable version)
Go to Edit>Preferences>Help System, and set it up as i shown in the earlier post.
Everything should already be set for you as Gimp will recognize it has the files.
Go to Help>Help and there you go.