Error code 80029c4a in QuickBooks 2015 usually indicates a problem with Windows installer files needed to run QuickBooks properly. Try reinstalling or updating the Microsoft Visual C++ packages on your system.
Also try running QuickBooks as administrator, disable antivirus temporarily, or reinstall QuickBooks 2015 completely. Intuit's site has tips on troubleshooting
Quickbooks error 80029c4a to fix the issue and open your company file again.