You could add the language key manually in the database, but thats a bit tricky and risky (MAKE A BACKUP!).

I'll try to explain:

Open PHPmyAdmin for editing the database.
Opten the table "ow_base_language" and look which ID your language pack has (usually ID 1 for english)

Go to the table "ow_base_language_prefix" and look for the ID for "groups".
In my case, the ID is "121". You'll need that later for adding a language key.

The next step might not be nececssary.
Go to the table "ow_base_language_key" and search for your strings "group_list_menu_item_invite" and "group_list_menu_item_my". If they don't exist, go on:
Sort by "id" (DESC), so you will see the latest language ID, click on "insert" and you will see three input fields:
- id
- prefixid
- key
add a new value for each and start with the ID, which is one number higher than the highest ID in the table (in my case: 10145, so I will use ID 10146)
For the "prefixid" you'll take the ID from the table "ow_base_language_prefix" (in my case: 121) and for the "key" you use "group_list_menu_item_my".
Save that and repeat that for "group_list_menu_item_invite" (don't forget to set the ID one higher!)
If the keys already exist, just note their IDs (in my case: 10129 and 10128)

Now the last step:
Go to the table "ow_base_language_value", sort by ID (DESC) again and add a new entry:
- id: one higher than the highest before
- languageid: "1" for english
- keyid: the ID from  "ow_base_language_key" (in my case 10129)
- value: what you want to have as text. e.g.: "My groups"

repeat that for the next ID (and as usual: +1 ID count) and set the value to "Invitations" or something like that :)

That might sound a bit complicated, but it's easy if you know to handle phpmyadmin.

- Hati

Hati ty...my problem with buttons is fixed ;)
Do you know how to fix about groups pictures and invite button does not show them?

I fix the problem with pics...but i stil dont see invite button in groups...any idea someone?