I also have been having the issue with the California Fiduciary Return (form 541) causing a failure to transmit due to Error Code 54.
Based on the most recent posts (thanks!) I tried it again and it worked! I have received the confirmation that both the federal and CA state return were filed.
The fix must have been done by Intuit on the server side, because it did not require an update to the Windows TurboTax Business program.
