Build error 1547 when enabling ActiveX server.

I am getting the following error when trying to build an exectuable: 

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Error 1547 occurred at Invoke Node in AB_EXE.lvclass:Build.vi->AB_Engine_Build.vi->AB_Build_Invoke.vi->AB_Build_Invoke.vi.ProxyCaller

Possible reason(s):

LabVIEW: There was an error generating the type library.

Method Name: Build:Application

This build used to work fine. I have tried mass compiling the project directory, recreating the build from scratch, rebooting etc. No luck. It seems to build fine if I dont have enable active X server checked but unfortunately it's required for this application. Any help appreciated. Thanks!