Your application can be filed by your relatives or friends. However, you have to be physically present in US when the application is filed. Please take a look at a re-entry permit case denied by UCCIS at:
http://uscis.gov/graphics/lawsregs/admindec3/i1/2003/FEB2703_01I1223.pdf
For more denied re-entry permit cases, please visit:
http://uscis.gov/graphics/lawsregs/admindec3/i1/index.htm
If you are not in US when you file I131, it is very possible that your application is denied.
Good luck.