Hi AndyFC, if you are using OS 3.2 then there might be issues with it.
Alternatively I have prepared VanillaTD 1.3 based on MorphOS sources, with built it movie player. With and without SDL
https://mega.nz/file/F4Fx2YrS#44js7a77DYgL-6XiZoSSdQULzm2O00fEoxQRTqKm3oI
and Red Alert port:
https://artishq.wordpress.com/