Texas Instruments TI-73 Manual Book page 51

Validation Error — Either this calculator does not have a
certificate to run the application, or electrical interference caused
a link to fail. Try to install the application again. If you continue to
receive this error, contact Customer Support.
Checksum Error — The software was not able to
TI GRAPH LINK
verify that the application was fully installed. Try to install the
application again. If you continue to receive this error, contact
Customer Support.
Other Calculator Errors — For information about other error
messages, refer to the error messages in Appendix B of the
TI 73 guidebook, or contact Customer Support.
TI-73 Geoboard Page 51