[ic] database/usertag/checkout issue

[Aaron Berg]

I have a strange database/usertag/checkout issue. The usertag works at
all times until the user clicks 'place order', then it dies on a
'database_exists_ref'. Is there something special a usertag must do
during checkout to access databases?

A bit more detail:

The catalog is based on the standard store using IC 5.4 and MySQL
4.1.20 on Fedora 4.
I've created a usertag which reads a set of tables to grab the correct
tax rate based on city, county, state, and country.  I've defined a
'SalesTaxFunction' which calls the usertag to get the tax rate.  This
usertag functions when called directly, or by 'SalesTaxFunction'.
This function is used on ord/finalize without issue to select the tax
rate and also to get the tax rate for display purposes.
When I press 'Place Order' the usertag dies on the first
'database_exists_ref' and logs the following error:
	Can't locate object method "FETCH" via package "DBI::db"

I then also get:
	Can't use string ("0") as a HASH ref while "strict refs"

I'm assuming the second message is a result of the first one.

Does anyone have any ideas or suggestions about how to track this down?