vico10,

Internal application error usually denotes a PHP error. Without further information, there's not much we can do to help. You should check your system log for further information. Alternatively you can try to temporarily configure your system as follows and try to reproduce the error:

$g_display_errors = array(
    E_WARNING => 'halt',
    E_NOTICE => 'halt',
    E_USER_ERROR => 'halt',
    E_USER_WARNING => 'halt',
    E_USER_NOTICE => 'halt'
);
$g_show_detailed_errors = ON;

WARNING - SECURITY RISK: the 'show_detailed_errors' config can cause MantisBT to display sensitive information about your system. We recommend to restrict its activation to a Test environment, only for as long as necessary. If possible, do not turn it ON globally, instead limit it for specific user(s) using the Manage Configuration page.

This is not a bug or feature request for MantisBT (you are asking for help on how to configure the system). I am therefore resolving this issue as "no change required".

Please use the forums to get support on customizing and using MantisBT (refer to http://www.mantisbt.org/support.php for links and further details).

Thank you dregad, Keep investigating