ORA-39142: incompatible version number 3.1 error work-around
Here's an interesting blog entry from Burleson computing that appears potentially useful for your circumstance.

From the site:


  There are two cases where it is possible to import into an earlier
  release:
  
  1 - Using the version parameter in Data Pump.  See my notes on
  importing between different releases of Oracle with Data Pump
  export/import 
  
  2 - Using a exp dump file with a Data Pump impdp utility.