The latest, as linked above, will run as a trial for a short time. No harm in trying it.
Be aware that if you create a project with it, older releases may refuse to load it, unless a change is made to a file.
Close the program, reopen without loading anything and go to OPTIONS | DISK tab. Clear Unused Cache Files -- then load the project.
If still no joy, do this, and we'll analyze what's wrong. Share the project. This is easy, quick and can be done privately. Just follow these steps...
Back up --- With your project on the timeline, click on MENU at the top-left. Click FILE|BACK UP PROJECT FILES TO FOLDER. Choose a folder and SELECT FOLDER.
Upload --- Use a free server - Google Drive, MS OneDrive, etc.* - to upload the saved, numbered FOLDER. Do NOT upload the individual VPJ or export file.
Get link --- Get a public link. Right-click the file and click SHARE. When using Google Drive, if necessary change "restricted" to "anyone with the link can view"
Share --- Click COPY LINK | DONE. Paste that link here, or click the folder at the top-right of this forum to message it privately to me. It won't be shared.
* Before uploading, right-click the folder, click PROPERTIES. Look at the File Size to confirm that it's not too big for the free space on the server.