I'll fix this in the next update, but here's a quick fix for you:
1. Launch the game, load your save file
2. There's a doctor on the second floor, Yamauchi Saki. Cancel her task. (For anyone else having this issue, you can try canceling tasks of all staffers).
3. You can unpause the game now and it should work
Thanks for the report! And let me know if it didn't work