Post installation

I have installed a Drupal which was configured and tested on a 4.1 database.
This Drupal configuration I ported to a 4.0 database, and removed the bottom line in every table created - because the character mapping made trouble.

Now I have an installation which gives me this error when submitting content:

is subcategories possible for a profile category?

i have a user profile category 'Academic' and i like to have subcategories like
"Graduation" & "PostGraduation".

"Graduation" will have 'College name' , 'course year' fileds. "PostGraduation" will have
'University', 'specialization' fileds

how to do this? is that possible?

thanks,

I never used Drupal before and must admin that I'm not familiar with Drupal inner workings, but now have to administer our company Drupal 4.6 based website. We have tried to enable the forum module and got this result, which doesn't look very "forumish" to me:

http://www.sintez.co.za/taxonomy_menu/12

Hi. I am trying to get a handle on how drupal uses free tagging. I've seen some examples, and it looks like just what i need. However, i am not sure about some basics:

is it possible to select from an existing set of tags? I might tag something from any one of my categories, but it seems that with free tagging i can use any string. ?
How do you consolidate a series of terms into a catgegory? does one need to do that?

Is there a book page that deals with this issue?

Please advise...

I am wondering if i should go with the category module, or just use the stuff that comes with drupal. What are peoples opinons of this? More importantly, if i start out using one method, can i reverse easily and try the other? I've read some good reviews of the module, but not really seen a critical comparison.. is that available anywhere?

Email sends from Drupal go to Junk folder. In Hotmail, this message apear at top of the message:

The sender of this message, xxxx@DrupalInstallation.com, could not be verified by Sender ID. Learn more about Sender ID.

Why messages send by Drupal could not verified by Sender ID?

It's the same at Yahoo too and always messages send from my drupal installation go to Junk folder. I never send spam emails and my domain is very new.

Does somebody have same problem?