problems w.bloggar

Hi everybody,
I tested w.bloggar. For me it´s a very good tool because at home I have just a dial up connection. And I think it has a lot of very good features.
Unfortunately I get a lot of erros while posting. For example:
“For some strange yet very annoying reason, the entry couldn´t be edited.”
Maybe there are some settings in WordPress which are not compatible with w.bloggar. Another reason might be encoding or charset.
I want to post to my blog in German so I have some of the extended chars.
Can anybody give my some hints to avoid these errors?
oerdec//