How can I export my project?

following!

It looks like your disk does not have enough free space for the media cache. Try to purge the memory (Edit > Purge > All memory & disk cache). You can also adjust the Disk and RAM settings in Preferences and see what happens. It does not guarantee success, but might help.

Try exporting to a different drive.

Are you working on your own PC. If it’s not is there a file limit size by and Administrator?