There has experienced the problem with the upload of tar and zip files to the vBulletine on
cPanel environment. These files required special settings to be done.

It required the settings in two configuration file.

First : php.ini

customize the php.ini file for the domain on which vBulletine is installed and set following parameter as per requirement

upload_max_filesize = nM

Second : my.cnf

Edit the my.cnf file to set following parameter

set-variable=max_allowed_packet=nM

* replace the n with required number.

restart mysql and httpd.

This should solve the problem.