I ended up a few times with these kind of errors while migrating to newer Flex 4 builds:
Description Resource Path Location Type
1044: Interface method invalidateParentSizeAndDisplayList in namespace mx.managers:ISystemManager not implemented by class _Main_mx_managers_SystemManager. example-project line 23 Flex Problem
Description Resource Path Location Type
1144: Interface method callInContext in namespace mx.core:IFlexModuleFactory is implemented with an incompatible signature in class _Main_mx_managers_SystemManager. example-project line 23 Flex Problem
The location/resource for these errors is the main MXML itself but that’s all you get. So you ask yourself what went wrong? A quick Google search does not help (until I blogged this hopefully) so where to start?
The problem is that you are mixing different SDK versions. In my case my project linked to a library which was compiled with a different SDK version and now the important thing: the framework linkage in the library was set to “Merge into code“. Change it to “Use default (external)” and you are fine.






I just opened up a project I had been working on for a while and my environment decided to lose it’s mind and throw the 1144 error. I’m on a super tight deadline and this is the sort of thing that just makes your heart stop. Google brought me to you and it solved it. Don’t usually post these, but I figured I owed you a “thanks for saving my @$$”. Keep blogging. We need you.
Thank you, I got the same error and was really concerned how to fix it.