Module development and code questions

Drupal4.7-beta4

After setting up Forum from administer-forum, then I start to test posting forum topic, however, I notice there are only subject box and body context, user have no choice where the new post ahould be, i.e. dropdown box for list of Forum containers or forums is missing, can anyone give me a hint?
Thanks

Hello all,

I am currently setting up a drupal site that is running the ecommerce.module. Everything on it seems to be working fine except the website wishes to take paypal (which is setup already) AND a mail in payment of a cheque or something along those lines. I saw there was a cod payment mod, is there a way to alter that to turn it into a mail in payment module? All it really has to be able to do is say where to mail in the cheque and who to make it out to.

If anyone has any ideas for this please let me know.

Thanks in advance,
txcrew

What or where are the rules which refine whether I can call a function in another module or call it via module_invoke? Also does module_invoke allow variable references to be passed to the invoke module, which is to say changed in the module invoking the other module?

hi,

I have a question: there are two modules out there which support ecommerce stuff - the paypal framework + paypal subscription modules and the e-commerce thing.

functions I want to cover:

1. paypal payment
2. after buying via paypal the user can download a pdf file
3. after buying, the pdf should be available for the user, if he is a registered user
4. if he is not a registered user, he can still buy the pdf, but after login the pdf is not available for him

Maybe this is not the right question - so i will likely end up posting this a couple times here.
=================

What do i do to have a module put a piece HTML code ONCE into my page ?

I was trying to use hook_nodeapi which sort of works.. except that my page has 3 nodes on it.. therefore it was doing this 3 times... which in FF it didn't seem to be an issue (not sure why not.. likely it was doing it but other 2 copies were buried).. but they show up in IE.

Hi - Working in 4.7, upgrading some modules in my site.

I have a multi-select box, that seems to be throwing the newly updated:
"An illegal choice has been detected. Please contact the site administrator."

Error message being discussed in this issues post a couple weeks ago, I must be the "hacker henry" mentioned in the post :) http://drupal.org/node/45821

I have narrowed it down to this multi-select box, if a user tries to submit without having made a selection.