You could change layouts by global variable... Then add a subevent for each particular level assuming the character position is going to be different everytime.
Although I'm not sure why you can't just put the character on each layout in the position that you want him to be when the layout starts.
Anyway I hope these screenshots will be useful...
Progress level by variable
<img src="http://dl.dropbox.com/u/44025915/LevelByVariable.png" border="0" />
Level Specific Action - Sub-event where you would set position of character
<img src="http://dl.dropbox.com/u/44025915/LevelSpecific.png" border="0" />