Module development and code questions

Hi all,

I have just started developing in Drupal and was wondering the following: Is there a way I can redefine some methods of an existing module without having to redo all the work manually when I install a new update of the module?
In fact I would like to be able to define the methods in a separate file and have them called instead of the default methods defined in the module itself... This way I wouldn't change the original files of the module but I would be able to override some methods.

Hi all,
I want to use project in order to have a ticket systems inside my portal, but I'm having a lot of problems with the subscribe component.

Registered users NOT receive e-mails of notify!!!

At the beginning I had problems with e-mails delivery in Drupal, but after I installed the SMTP module (as says here http://drupal.org/node/59085), problems now are restricted to project issue module.

Just someone just confirm that the forms API for 5.1 ignores any browser supplied information for hidden elements of forms? I'm seeing the values I want in my $_POST data but the $values array in my submit function contains the original values filled in to the form array. Am I doing something wrong, or is that how it's supposed to work?

i need to add in the fly a taxonomy to a book. I've put an extra field
in my book (a cck node) in case the user want to add a new taxonomy
without going to the form taxonomy.

I've a custom module to handle this:

I have a web page in 3 languages. It's a library, the main node it's a
book.

I have some taxonomies, for example the book category, tranlated to the
three languages. I'm using i18n module.

I don't want to translate the book node (only the name of fields is
translated with t() function).

The problem is if i put a book in a english taxonomy it doen't show in
any of the translated taxonomies.

For example:
I have the Book: "El Quijote"
and the category: en "Novel" es "Novela" ca "Novela"

I am getting this error when I try to submit a story:

user warning: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') AND th.tid IS NULL' at line 1 query: SELECT DISTINCT td.tid FROM term_data td LEFT JOIN term_hierarchy th on td.tid = th.parent WHERE td.vid IN (8) AND td.tid IN (11,0,) AND th.tid IS NULL in C:\Program Files\xampp\htdocs\drupal\includes\database.mysql.inc on line 172

I am using XAMMP,

PHP: 4.4.0 MYSQL: 5.0.27

installed modules:
02/06/2007 12:22 PM aggregator
02/18/2007 02:32 PM bbcode
02/06/2007 12:22 PM block
02/06/2007 12:22 PM blog
02/06/2007 12:22 PM blogapi
02/06/2007 12:22 PM book
02/13/2007 03:57 PM ck
02/06/2007 12:22 PM color
02/06/2007 12:22 PM comment
02/06/2007 12:22 PM contact
02/06/2007 12:22 PM drupal
02/12/2007 12:16 PM ed_readmore
02/06/2007 12:22 PM feedback
02/06/2007 12:22 PM filter
02/06/2007 12:22 PM forum
02/12/2007 03:46 PM front
02/06/2007 12:22 PM help