I have been trying to get my 710 to 7.8 with cab sender and it keeps telling me that CHOICE is not an internal or external command. I have re downloaded multiple time with the same outcome. I tried using seveneighter but says it is not a win32 application. Same with navifirm. I am running out of ideas.
Someone please help me. I have been at this for too long.
I'm not too sure how to remedy the problem with .cab files not being sent. Perhaps legacy reasons?
I've also noticed that you stated that you've been trying to run seveneighter and Navifirm, with no luck. As you can see, because of legacy reasons, seveneighter or navifirm will NOT run on Windows XP because of missing drivers and such that is only available in Windows 7 or Windows 8. (Though the latter tends to make seveneighter crash. I've had no problems with seveneighter on my computer, however.)
Try upgrading to Windows 7 or 8. If money is an issue, use a family member's, friend's, neighbor's, or cousin's computer running either two to update your lumia 710.