for postgres it is not valid to use integer(x) http://www.postgresql.org/docs/8.1/static/datatype.html#DATATYPE-NUMERIC
postgres maps all integers to a own name.
<column name="id" phpName="Id" type="INTEGER" size="4" ...
... integer(4) ....
which fails with postgres.
as far as i reserched it is also invalid for ansi sql. https://en.wikipedia.org/wiki/SQL
would be good if it would be converted to a regular integer for postgres (or maybe for all databases, as far as i know mysql is fine with smallint, integer and bigint is it?.
If it's true, then you just have to add a new rule to this class: https://github.com/propelorm/Propel/blob/master/generator/lib/platform/PgsqlPlatform.php using the PropelTypes::INTEGER constant.
@themouette do you use INTEGER types in your schema?