Some problems is a vague start to help...

For example if you have problems to connect to your mailserver and have already checked your settings, you could start an X Terminal window and enter
export "CAMEL_DEBUG"="all"
to enable the debug mode of the mail library, and after that
/usr/bin/maemo-summoner /usr/bin/modest.launch -s > /home/user/MyDocs/.documents/log 2>&1
to start the email application. Then try to connect to the mailserver. You will get a logfile named "log" which will be in your Home directory (please check for confidential data before uploading anywhere).