Well, hate to tell you this, but I have never tried touiteur before. I downloaded the free version from the market and signed right in. Looks like a neat app, but I am having no issues with it and Sapphire 0.8.4.
Not currently on saphire but was on 8.4 with 928 theme and toutier (spelling) worked without a problem.
some of the keyboards have been putting in spaces automatically make sure theres not a space where there shouldnt be in your login.
I think it's an app issue. I use it and Sapphire and haven't had any problems. That did happen once to me on BB though so I reinstalled Touiteur and it never happened again.
i use touiteur as my main twitter app and had no issues at all, only issues i'm having with sapphire 0.8.4 is the launcher restarts/redraws after exiting an application but that problem seems to be w/ every froyo rom, Sapphire is my new fav rom no doubt