1st: How i can do a "groupsearch" inside groupjive? i've found this component but is for joomla 1.5... it will work with 1.7? it's work fine? i don't want to create problem to my site becouse it's almoust finished! ( www.joomlapolis.com/cb-solutions/directory/community-building/searching/groupjive-search-plugin )

Navigate to a category that has groups then use the search input box. Yes, it works fine on any CMS version that CB does (so yes it works on J1.7).

2nd: I wanna make possible for the registered user to create group to the frontend, i had make the change in the configuration but nothing... why? (conflict with other module?) see the attachments image

Have the user navigate to a category and click "New Group" on the categories menu. If the link is missing then edit the category and ensure "Create" is set to "Enabled". There is global configuration then there's also category by category configure. Please ensure you're using GJ 2.5 RC1 (available in Professional downloads section) as GJ 2.4 has a bug that resets "Create" back to "Disabled" everytime you edit a category.

& also, how i can edit the layout of the groupjive section?

It's purely template based. You can change the frontend templates from the below location.

components/com_comprofiler/plugin/user/plug_cbgroupjive/templates/

3rd: I wanna create a sort of "facebook events", created by admin (i've tried jevent) but with the possibility of join the event by the users... what can i do?

Not sure what this has to do with GJ? CB has no event extension. GJ events are specific to a group so you must have the GJ events integration installed then navigate to a group and utilize the Events tab.

for the event there are some in plane about this??? the only extension i've founded it's eventlist... but it's not official supported in joomla 1.7!

Not that I am aware. JEvents is J1.7 compatible and free; maybe give it a try for your event needs?

extensions.joomla.org/extensions/calendars-a-events/events/events-calendars/95