Hi,
Ok I think at least we have found the source of the problem. You say you cannot arrange those numbers into a normal configuration - why not - do you get the same error message as me in "outlook-enter-valid-number.png" attached?
As you can see - I cannot save invalid numbers so I'm unable to test it against GogTasks. That makes it more difficult to fix the error, but maybe not impossible. If you cannot solve the problem in your end, I will make an attempt on that.
What I want you to check first is your regional settings though. See "control-panel-regional-settings.png" attached. If you could please check the "decimal symbols". If that field has a wrong value (for instance ",.,"), maybe you could try to set a correct value or reset to default Portuguese I'm assuming you normally do not express decimal symbols as a dot followed by comma and another dot in Portugal ;-) ) Maybe changing it to for instance English, apply, and then back to Portuguese will fix the problem.
Again, if you are unable to fix the problem, get back to me and I will spend some more time in the GogTask code to see if there is anything I can do to fix it there.