If you ever get stuck in the game, you can click on the question mark in the lower right corner for hints. Anyway, to get through the cave, you need to follow Smiley's trail of cigar stubs. Sometimes you might need to jump across chasms by using the rock pillars. If you place your cursor over them, it will change to a pair of feet with two lines. That means that you can jump.
Can you add a screenshot so I can have a better idea of where you are in the cave? Or maybe you could watch this clip from a video walkthrough that someone posted on youtube. The cave part starts at 8:21. http://www.youtube.com/watch?v=Ad0TeQI5Fbc
Comments
http://www.youtube.com/watch?v=Ad0TeQI5Fbc
The rest is at the beginning of this clip.
http://www.youtube.com/watch?v=M8nroyszeaQ
I hope that helps.