You can run Eclipse using the VM from IBM Developer Kit for AIX versions 
1.4.2 and 5.  The IBM Developer Kit for AIX can be downloaded from:
http://www.ibm.com/developerworks/java/jdk/aix/service.html

To run Eclipse on AIX, you must ensure that your AIX install includes the 
necessary service updates.  Please use the following command to determine the 
service level of an AIX fileset on your machine:
	lslpp -l | grep FilesetName

Please see the section below that corresponds to your AIX release.

AIX Version 4.3.3:
	For fileset X11.base.lib:
		If service level < 4.3.3.79, you must apply APAR IY27694 
	For fileset X11.motif.lib:
		If service level > 4.3.3.81, you must apply APAR IY41939 

AIX Version 5.1:
	For fileset X11.base.lib:
		If service level < 5.1.0.25, you must apply APAR IY27695
	For fileset X11.motif.lib:
		If service level > 5.1.0.36, you must apply APAR IY41942

AIX Version 5.2:
	For fileset X11.motif.lib:
		If service level > 5.2.0.0, you must apply APAR IY41944

IBM APARs can be downloaded from:
http://techsupport.services.ibm.com/server/fixes