Failed to read and display image file from gnuplot

[applibres]

Hi, when I tried to run:

plot sin(x)

I get this message:

Failed to read and display image file from gnuplot. Possibly:

1. You have plotted to a non interactive terminal.
2. You have an invalid expression.

It is necessary to set a terminal?

[has2k1]

Ordinarily, it is not necessary to set a terminal. Maybe there is a startup file with interfering settings!