Stack Overflow is not allowing me to suggest edits. I know that some unaccepted edit suggests caused this problem.
I just want to know how many unaccepted edit causes this problem, so that in the future I shall be aware of it.
We can't answer this because then people would try to get one edit under the limit to "game the system." It is probably made up of more than one factor as well.
Simply learn from your rejected edits and you will be able to get more of your edits accepted.
For example, see one of your edits that were rejected. You added some code. This would be better as a comment, telling the author of the answer that there is indeed a way to do that in Opera and IE.
This edit of yours also has the same problem. Tell the author of the answer in a comment.
I just want to know how many unaccepted edit causes this problem, so that in future I shall be aware of it.
No, that's now how the system works. You don't improve by learning how the system determines whether or not to ban you. You learn by reviewing the edits that got rejected and figuring out what you need to do to suggest better edits. Go look through your suggestions, find the rejected ones, and learn from the advice the reviewers have given you.