When using ANT <fdt.launch.application> as always, I found out today (and previously with other 4.6 betas) that I get an exception during compilation: java.lang.NullPointerException at com.powerflasher.fdt.core.launch.debug.DebugSessionManager.getDebuggerFor(DebugSessionManager.java:50) at com.powerflasher.fdt.core.launch.debug.DebugSessionManager.launchSessionFor(DebugSessionManager.java:97) at com.powerflasher.fdt.core.launch.debug.DebugSessionManager.launchSessionAndKillOld(DebugSessionManager.java:137) at com.powerflasher.fdt.core.internal.launch.debug.concrete.DebuggerStarter.run(DebuggerStarter.java:47) at com.powerflasher.fdt.core.launch.AbstractTargetStarter.runListenerStarters(AbstractTargetStarter.java:61) at com.powerflasher.fdt.core.launch.swf.SwfStarter.run(SwfStarter.java:58) at com.powerflasher.fdt.core.internal.launch.compile.concrete.CompilerProcess$1.run(CompilerProcess.java:226) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:54) Session-data: eclipse.buildId=M20110909-1335 java.version=1.6.0_29 java.vendor=Apple Inc. BootLoader constants: OS=macosx, ARCH=x86, WS=cocoa, NL=en_US Framework arguments: -product com.powerflasher.fdt.product.product -keyring /Users/joeyvandijk/.eclipse_keyring -showlocation Command-line arguments: -os macosx -ws cocoa -arch x86 -product com.powerflasher.fdt.product.product -keyring /Users/joeyvandijk/.eclipse_keyring -showlocation I am only calling FDT ANT tasks like they are working with Flex SDK 4.5(.1) with all AIR versions (2.6 / 2.7 / 3.0), but apparantly something is crashing. It occurs when building for AIR3.0 and FP11.0 + AIR3.1 with FP11.1. Its a big project so I cannot share it, but because it previously worked with different AIR versions (and with or without AIR3.1 / FP11.1 changed definitions) but not any more with this new Flex SDK. I saw also that the SDK from opensource.adobe.com (4.6.0.23201 Adobe Flex version) is default now an AIR setup (possibly due to flash plugin choices). Any tips on sharing more debug information would be helpful, while I only grasped it from the Error Log in Eclipse. Hope you can discover whats happening, while this error I also got using the beta/prerelease versions of Flex SDK 4.6, so I presume it has to do something with the way FDT uses the Flex SDK compiler. FYI