i am using sketchup 8 for a while now, i have downloaded few extensions but i am not able to add them in my sketchup as it seems that my sketchup doesnt have a install extension button in extension dialog box. is their any way to install those plugin in my sketchup.
I can’t remember when the change was made to actually installing extensions…and it’s a long time since I’ve used V8. It could be that you were still able to simply drop .rb files into the program’s Plugins folder. Try copy/pasting a single .rb file and see if the extension shows up in one of the menus.
Edit: I just checked and saw that V8 was when the new systm kicked-off. If you really don’t have an “Install Extensions” button on the Extensions tab in Preferences, then you should try a re-install (preferably as Administrator.) If you have the Sketchucation Plugin Store extension, then you can auto-install stuff from there without going anywhere near Preferences.
It sounds like you have the original release of SU8. The Install Extension button was added with the first maintenance release. Reinstalling what you already have won’t make the button appear. SU8 is no longer available and features like the 3D Warehouse and Add Location no longer work in it anyway. It’s time to upgrade to SU2016 now.
An alternative would be to rename the RBZ files to .zip and then extract the contents of the zip file to Plugins. Just make sure you don’t modify the file structure within the rbz file.
It was V8 M2… 
So if he hasn’t got one of the later releases, he should still be able to just drop rb files into Plugins, nicht wahr?
Yes, richtig.