Opening a Visual UML 3.5 with 6.5

I am trying to import a XMI created in version 3.5, which has significant information loss.
I also tried to open the .UML .DTD which returned an error.
Is there any way to pull in the project from version 3.5 into 6.5 without data loss??

Hi Theodorel,

Thanks for your post. Would you mind to send me the XMI file for investigation? Thanks in advance!

Best regards,
Lilian Wong