Rails 3.2 Postgres Save Error "ActiveRecord::StatementInvalid: PG::Error: ERROR: Syntax error near 'T' at position 5"
I just had a similar problem, on Rails 3.2. If you're not using Rails trunk (working towards 4.0), it doesn't understand the hstore natively - you need to define a serialization coder (which is provided by the activerecord-postgres-hstore gem), like so:
class Example < ActiveRecord::Base serialize :data, ActiveRecord::Coders::Hstoreend