Problem with Kunena

For the first 2 issues, can you ensure that you have the JFBConnect User plugin enabled and properly ordered. You should see it's status on the JFBConnect Overview page in the admin area. If there are any red 'X' or error messages, please correct those. That's likely the cause of the first 2 issues.

The Login button is displaying like that due to your styles. I'm assuming you specifically mean the black box around the button. The specific style is coming from Kunena, which is putting a border on the following styles (which is what FB uses for it's button styles):
test.guru99.com/components/com_kunena/te...GHT/kunena.forum.css
#Kunena .button:hover, #Kunena .fb_button:hover, #Kunena .fb_button:focus {
background: #000040 none repeat scroll 0px 0px;
border: solid #404070; <-- This is causing the black box
color: #FFFFFA;
font-size: x-small;
padding: 0px 4px;
}

Hope this helps!

For the button styling, if you get rid of every style that I mention above, it looks normal. I'm not sure why it's messing it up that bad, but those styles are why it does not look correct.

Your picture actually speaks a thousand words above too for the User Plugins. The 2nd plugin called "juliaredirectlogin", I'm assuming, redirects the user to a new page. If this is the case, then that would prevent any plugins (or any activity) after that plugin to occur as a lot of the time, redirects are 'instant'. Try moving the JFBConnect User plugin ahead of the redirect plugin and see if that fixes your issue. While you're at it, you probably should move the Acajoom User Sync plugin ahead of it too, as I'm guessing synchronization is not occurring properly there either.

Try that, and if it doesn't work, we'll log in and do what we can to narrow the problem down further.