Rasmussen has a long history of methodology problems, and is generally quite conservative-leaning and sometimes much more off the mark than other pollsters.

This poll in particular has a couple of big issues--those are both leading questions, and don't fully reflect the reality of the situation. The first question, for instance, ends on " until the federal government improves its ability to screen out potential terrorists from coming here?" -- leads the respondent to answer in the affirmative. It implies that there is a problem with the government's current ability to screen out terrorists, and implies that the respondent should support such action. The second question has the same problem, and also doesn't make it clear that the "temporary block on visas" is including visas already issued, to travelers already in transit, and even includes green card holders and people already resident in the US.

It is quite likely that Americans who might support some kind of ban, or who might support a ban in some circumstances, do not support this ban in these circumstances. Hard to say much more than that until a better poll is released.