404 - Component not found

I did try to find what am I doing wrong...
I get this error again and again. It is a new site and I am just starting.
What is installed already is Community builder, kunena and your component.
No idea what I should do to make the facebook connect work.
Thank you for your support
Eagle

Thank you for your reply;
I disabled SEF and now this problem is solved.

Is it because my joomla is on sub folder?
Since I would like to have this new site SEF (I intend to direct a ad on domain to that folder when I am done building),
Is it going to be a problem that can not be solved unless it is hosted on the home folder?

Another problem I try to solve;
I still get an error, after registration, concerning image size. I did try to rase the size limits but probably I don't do the right thing or at the right place.
Here is the error;
Warning: filesize() [function.filesize]: stat failed for jfbc_xxxxxxxxpic_tmp in /home2/xxxxxxx/public_html/arcb/administrator/components/com_comprofiler/imgToolbox.class.php on line 467

my site is being built now under;
<!-- m --><a class="postlink" href="arcb.awakenedreality.com">arcb.awakenedreality.com

unfortunately I can't give you my admin because, since that fix I can not log into the admin any more.
<!-- s:-( --><img src="{SMILIES_PATH}/icon_e_sad.gif" alt="" title="Sad" /><!-- s:-( -->
The site work well, but administrator can not log in.
I tried all that I know; a new pass word. (using the forgot password), but the new pass word don't let me in as well.
I was creating a new supper administrator, still can't log in.
What could I do next?

This same situation happened to me a few days ago, but I was not sure why. Now it is the second time and it looks as if the problem is because of this installation.

ps: Yes, the Avatar was imported correctly even if there was an error message.
and most errors were happening while using Safari.
Now;
I can't be sure what is the cause of loosing my admin and I did try to get in using all recovery and admin creation tactics.
At the end I decided to go back to a backup from two days ago. (Two days of work are gone <!-- s:-) --><img src="{SMILIES_PATH}/icon_e_smile.gif" alt="" title="Smile" /><!-- s:-) -->...

The big question;
should I try again to configure JFBConnect on the sub folder (that will be a add one domain as soon as I am done building)
or
shall I reorganize to do that on a home directory?
is JFBConnect able to perform good on an addon Domain that is directed to a sub domain on another folder (not the home folder)?