Module development and code questions

Although originally working just fine, I am now getting these errors when testing using paypal.module using IPN to process payments:

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/cart/cart.module on line 295.

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 465.

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 508.

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 513.

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 518.

warning: Cannot use a scalar value as an array in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 521.

warning: Invalid argument supplied for foreach() in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 523.

warning: Bad arguments to implode() in /home/nickfeld/techstockinsights.com.nbsweb.net/html/newscenter/modules/ecommerce/store/store.module on line 531.

In sending an email to the mailhandler, what commands, e.g., promote=1, would be included in the email to denote what role can access the content of the node being handled?

I am considering writing some code that uses the Curl library. I know that some web hosts do not have curl installed, and my code would break on such systems. I'm curious to know what percentage of users would have a problem running code that used curl?

To find out if your server supports curl functions, look at the output from the phpinfo() function and look for a section titled "curl".

Your answers would be greatly appreciated.

I want to try to implement the groups.module for 4.5; Is it possible that the groups.module can work at all with drupal 4.5, and if so, how do I go about it? I tried copying and pasting the patch data into the node.module file for example, but I still could not view the site. The site was working fine before the groups.module.

Our site is using forum topics as the primary organization of information, and the forum page as the primary view for users Recently, however, we wanted to add the calendar functionality offered by the event module. Having done so, we felt that it would be very useful to treat posted events as forum topics, so that as they were posted they would appear in the forum list and thus be brought to people's attention. I couldn't find a good way to achieve this blending. In the end, I hacked through the forum module, adding 'event' as another type of node on which forum did all its stuff.

In a previous post, I raised the question of stories versus forum topics, and why they were different. I seem to have run into the same sort of question again. The task of bringing a new posting to someone's attention is met ideally by the forum interface. But the calendar interface is also a natural interface to the same data at other times. In the current design, it is only the front page that is able to display arbitrary types of items, while the forum page is limited to displaying forum topics. This seems an unfortunate linkage, since the forum page is a nice interface to other topics as well---our users prefer it to the front page, because they like to see the compressed overview offered by the forum page rather than the list of expanded stories offered by the front page.

I am working on a questionnaire module, which will redirect the user after login to ask a number of questions. This is easy to do using the _user hook. However, I would also like to be able to temporarily suspend a user's access to the site, so that, until they have finished entering the data, they cannot gain access to any site content.