I have no oracle db to test, but can you try changing the following line in db/migrate/20090730152224_create_ptables.rb

t.string :layout, :limit => 4096, :null => false

t.text :layout, :null => false

It's not worked, because Oracle needs to set size for datatype. I change this as follows:
t.string :layout, :limit => 4000, :null => false
4000 is max size for datatype varchar2

Variant of a solution of a problem 2:
Add in if .. end condition else "do nothing" :)
For example in 20090915030726_change_report_field_type_to_text.rb add:
if ActiveRecord::Base.connection.instance_values["config"][:adapter] == "mysql"
execute "ALTER TABLE reports MODIFY log text;"
else
'do nothing'
end

Nikolay Aralovets wrote:

Variant of a solution of a problem 2:
Add in if .. end condition else "do nothing" :)
For example in 20090915030726_change_report_field_type_to_text.rb add:
if ActiveRecord::Base.connection.instance_values["config"][:adapter] == "mysql"
execute "ALTER TABLE reports MODIFY log text;"
else
'do nothing'
end

would you like to submit it as a patch for this ticket? (best if you want to use git so we can keep your details within the official foreman repo).