Audition has reached the limit of Audio files???

Hey,

I tried to edit some Multitracks (.wav file) inside Audition, but Audition wont me import them.

I create a Multitrack Session (192khz, 32 Bit, 5.1) and add the Audio files (43 Tracks).

Then it says it needs to convert them to the project sample rate (which is as usual) and then this errors comes up:

Audition has reached the limit of audio files that can be used by the application. Close some files to continue.

Why does this happend? I never had this before...

Thanks for your help!