If this project file was created with an earlier version of Captivate (e.g. Version 3 or 4), remove all instances of Text Animations and replace them with ones from Captivate 5 (if that's your licensed version) or 5.5.
All text animations were created with Captivate 5, but I will try your suggestion anyway. Thanks.
P.S. It's strange that it only crashes when inserting animated text.