Unable to send email messages on Mac (OS X)

I am working on Mac OS X 10.5.5 and Lotus Domino Web Access. I can read my email but not much else - if I want to send a message, reply to a message, forward a message, I get the following:

‘Domino Web Access Warning. Sorry, we were unable to process your request at this time. If you are unable to continue working in your mail file, please dismiss this warning and then select View, Reload from your browser’s menu.’

Reloading doesn’t help. I have resorted to sending emails from my work email account through Gmail because I haven’t been able to figure this out. Can anyone advise me, please?

Thank you.

Subject: Unable to send email messages on Mac (OS X)

Perhaps one of the links in this search will help:

http://www-10.lotus.com/ldd/nd6forum.nsf/Search?SearchView&Query=Access%20Warning%20AND%20mac&SearchOrder=0&Start=1&Count=100