Can't edit my Excel files on WP7 Mobile Office

[rsshirlevel]

My probleme is that I can't edit that kind of Excel files on WP7 Mobile Office, which files I previously edited/modified on Skydrive (on the internet).
I can open Excel files on my WP7 Mobile Office, but I can't edit it. I have only similar datas and functions on Excel files, no pictures, no chart, no frames...
I didn't recognized this probleme before (before 28.01.2013.)

Does anything changed on Skydrive on this weekend?

Can you help me, what could be the probleme?

Thanks,

Rudolf