how to activate gimp photoshop layout ?

i dont know, but for me i went ahead and installed everything and then ran gimp, and it ran just fine, faster than prior versions. still buggy though.

So, you've run GIMP at least one, and the layout isn't as specified in the screenshot above? You shouldn't have the background unless you install the background plugin as well, but the placement of the palettes should be the same.

Did you let the installer automatically find where to install to? You should be installing to your GIMPPortable folder.

To make sure You have no corrupted download extract gimp to your desktop , proceed as below then copy it over to Your USB drive.
goto
%Your drive%:\PortableApps\GIMPPortable\Data\settings\
and -if there - delete the files "sessionrc" and "sessionrc-backupbeforepslayout",
then start gimp once and close it again, make sure You have no corrupted pslayoutinstaller, then install the pslayout, run gimp again, it should look like the picture you mentioned. If not there might be a corrupted gimp install.

have no idea.You run it on windows XP?The sessionrc will be created after the first run...so I don´t have no more suggestion, perhaps anyone else...?

to make it clear:
Gimp doesn´t look like Adobe CS3 afterwards , it´s just a rearrangement of the tools appearance photoshop like
goto data/settings, open a file called sessionrc with notepad
and replace the contents by:

# GIMP sessionrc
# 
# This file takes session-specific info (that is info, you want to keep
# between two GIMP sessions).  You are not supposed to edit it manually, but
# of course you can do.  The sessionrc will be entirely rewritten every time
# you quit GIMP.  If this file isn't found, defaults are used.

(session-info "toolbox" "dock"
    (position 131 -4)
    (size 128 746)
    (open-on-exit)
    (dock
        (book
            (current-page 0)
            (dockable "gimp-tool-options"
                (tab-style preview)))))
(session-info "dock" "dock"
    (position 440 0)
    (size 250 767)
    (open-on-exit)
    (aux-info
        (show-image-menu "false")
        (follow-active-image "true"))
    (dock
        (book
            (current-page 2)
            (dockable "gimp-navigation-view"
                (tab-style name))
            (dockable "gimp-histogram-editor"
                (tab-style name))
            (dockable "gimp-brush-grid"
                (tab-style name)))
        (book
            (position 255)
            (current-page 0)
            (dockable "gimp-color-editor"
                (tab-style name)
                (aux-info
                    (current-page "GimpColorSelect")))
            (dockable "gimp-undo-history"
                (tab-style name)))
        (book
            (position 542)
            (current-page 0)
            (dockable "gimp-layer-list"
                (tab-style name)
                (preview-size 16))
            (dockable "gimp-channel-list"
                (tab-style name)
                (preview-size 32))
            (dockable "gimp-vectors-list"
                (tab-style name)
                (preview-size 32)))))
(session-info "toplevel" "gimp-file-open-dialog"
    (position 126 102)
    (size 768 576))

(last-tip-shown 14)

# end of sessionrc 

That should work, if not, there´s perhaps a problem with the launcher/gimp not reading the Data/settings folder contents

just use the uninstaller linked to on the Plugin's page.

there's an uninstaller on the photoshop layout page.