To dream of pants represents discipline. A reflection of your ability to stick to something, stay on track, or stay on message. It may also point to work ethic or will power.
To dream of being pantless or that your have fallen down represents feelings of embarrassment of having lost your discipline. Feeling unfocused, lazy, or easily manipulated.
Consider the color and style of pants for additional symbolism.
Example: A man dreamed of seeing a man wearing beige or khaki colored . In waking life he felt a strong need to be very focused on doing his job right.