TypeError (can't convert Bignum into Hash):

This error has been driving me nuts. It happens with no regularity or
pattern and causes a 500 App error. Refreshing will always display as
normal (http 200)

The back trace always starts with

TypeError (can’t convert Bignum into Hash):
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/connection_adapters/mysql_adapter.rb:342:in
update' /usr/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/connection_adapters/mysql_adapter.rb:342:inselect’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/connection_adapters/mysql_adapter.rb:342:in
select' /usr/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/connection_adapters/mysql_adapter.rb:175:inselect_all’
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.4/lib/active_record/base.rb:390:in
`find_by_sql’

but it comes from several different find_by calls. find_by_sql and
find_by_id

I’m running Rails 1.16 with ruby 1.84 on Mongrel 0.3.13.4 behind Apache
2.23 on Debian 3.1r3 with MySql 4.1

Anyone seen this or got ideas on how to further track this down??
Thanks
Sam