Urgent.. 4 x Warnings while I am trying to login to admin

All of a sudden all these warnings ?? and can't see my admin login page. My cart with the attributes isn't working either. Any connections?

Here are the warnings at the admin login. Can this be fixed?

Thanking you in advance.

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/ustar/public_html/store/includes/classes/shopping_cart.php:3787) in /home/ustar/public_html/store/includes/functions/sessions.php on line 108

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/ustar/public_html/store/includes/classes/shopping_cart.php:3787) in /home/ustar/public_html/store/includes/functions/sessions.php on line 108

Warning: Cannot modify header information - headers already sent by (output started at /home/ustar/public_html/store/includes/classes/shopping_cart.php:3787) in /home/ustar/public_html/store/admin/includes/init_includes/init_templates.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at /home/ustar/public_html/store/includes/classes/shopping_cart.php:3787) in /home/ustar/public_html/store/admin/includes/functions/general.php on line 21

Tutorials/FAQ's in the top nav bar
https://www.zen-cart.com/tutorials/index.php?article=97
https://www.zen-cart.com/tutorials/index.php?article=87

Ok Thanks . Did all that and found no empty spaces etc. and the fix file reported that everything was in order. Still have the same message naturally.

ooops you were right Kobra.

After having a second look at the warnings my shopping_cart.php had empty lines after the ?> ..I don't get as I do not remember playing with that file today (since it only happened today) . ...

home/ustar/public_html/store/includes/classes/shopping_cart.php:3787 >>> line was the last line in the shopping_cart.php code

Many of the 1.3.8a class (and other?) files have empty lines after the last ?> by default.

Why is that?

It worked after deleting the files. ....ahh I see they (Zen Crew) want us to learn PHP :-) ..we are trying..