You should not experience any problems and the program interface is fairly self explanatory however the most common questions are answered below.

Status Failed
If your tweet fails to be posted to twitter then the status is changed to failed.
The most common reason for a tweet not being sent is a duplicate tweet has attempted to be posted.

Twitter do not give exact criteria of what constitutes a duplicate tweet.
We suggest you look for the failed tweet text in your past twitter statuses.
If the failed message matches your last tweet or appears in your past tweets within a 24 hour period then this will be classed as a duplicate tweet.
Note twitter decides this not Sweeter Tweet.

If you have programmed a duplicate tweet then simply change the text, time or frequency.

Sent but not sent
When you program a new tweet if the time and day is before current time or day then it will be marked as sent.
i.e if it’s Tuesday and you program a weekly tweet for Monday or it is 3PM and you program a daily tweet for 10AM
Daily and weekly tweets are automatically queued for reset at midnight daily and midnight Sunday respectively.

Any problems tweet to @sweeter_tweet