1. Control Panel > Folder Options > Show hidden files and folders

2. Mozilla Thunderbird - Accounts > View settings for this account
a. Server Settings >
b. Local Directory >
    c:\ Document and Settings\Soufian\Application data\Thunderbird\Profiles\szyss4v.default\mail

3. Copy "mail.javaplant-1.net\inbox.sbd"

4. Go to other computer (like step 2)
    c:\ Document and Settings\Soufian\Application data\Thunderbird\Profiles\szyss4v.default\mail

5. Paste the content of inbox.sbd to inbox.sbd of mail.javaplant-1.net on that computer (overwrite)