Unable to Upload JBF Connect for update.

Without any specific details, it sounds as if you might be running into the default upload size allowed by PHP.

Please try editing your php.ini file and updating it to these settings:
After you make the changes and restart Apache, please go to the System -> System Information -> PHP Information section in the Joomla Admin area. Then, search for the values you updated "upload_max_filesize" and "post_max_size". There will be a few columns after each value. The first column is the "Local" value, which is what is currently being used. Please make sure that is at the 3M value you specified above to make sure the values took effect and then try the installation again.

If this doesn't solve your problem, please provide more details, such as any error messages you are seeing, etc.

-Melissa