Andy,
The Gmail IDs can be used to login into Yahoo, the Group settings allows for using a Gmail or a Yahoo email address as the primary one. My ID, now, is the Gmail one, and I can browse, reply, upload/download files.
What's confusing about Shigematsu-san is that he can login, post, view files, but not download them. Which is really strange, indeed.
Shigematsu-san, you said that you made another account and you could login and make changes, as well. You also said you want to change/modify your Yahoo ID. Combining these two togehter, why not delete that Yahoo account and then make another one the way you wanted? Or just use the newly created ones.
Vlad
