I created a scheduled transaction (bi-monthly salary transaction) and
missed entering an account for one of the splits. I requested the
transaction to automatically run.

When the transaction ran, gnucash ended up in an endless loop producing the
following output in the .xsession-errors log file ...

** CRITICAL **: file gnc-transaction-xml-v2.c: line 443 (set_tran_date):
asserti
on `tm' failed.

** CRITICAL **: file gnc-transaction-xml-v2.c: line 443 (set_tran_date):
asserti
on `tm' failed.
Error: create_each_transaction_he...(): Common-commodity difference:
old=USD, ne
w=(null)

Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Null kvp_val for account
Error: create_each_transaction_he...(): Unable to find common
currency/commodity
.

I have a workaround.

1) Kill gnucash (well the glade process)
2) edit the xml file and for the offending transaction change the
<sx:autoCreate>y</sx:autoCreate> tag to
<sx:autoCreate>n</sx:autoCreate>.
3) restart gnucash and choose the option not to enter the transaction.
4) Now use the transaction editor to correct the missing account.