Do I need to be active in the forums to be cable to host my website.

In other words: Is their any rule that says "NO Activity at forums means no website".

Please Help me out... IT's importent for me

Yes, the Hosting requires posting activity, however, you can accumulate posting credits once you are Hosted and not post for a period of time if you maintain a positive credit status. Or you can purchase Hosting credits.

As a new member, you will want to read the articles in the Trap17 README found above the shoutbox on every page.

Enjoy.

Ho much do I need to post to have my website running

Depends on the quality of your postings. It would take a large number of small, one-line posts like that one to earn a full credit, but with some effort, and with your computer background, it will not be difficult to earn credits.
The number of credits you have is on the Forum index page. Check the number of credits you have, then make a good, quality post and re-check the number. That will tell you how many credits the post is worth, so then you will have an idea about how easy it will be to earn credits.

Is there any minimum number of credits that I would have to maintain to be alive?

To get hosted in the first place you need either 1O or 3O credits, after that you need one credit per day, so the minimum is one credit, after that your site get suspended untill you get more credits at which point it is viewable again. Nothing will be deleted in this period. If your credits reach a big negative number the website will be deleted.

but so long as you have 3 or 4 credits then you can be fairly sure that, even if you cant get online for a few days, your website's presence is safe.

The minimum amount needed to stay alive is 0.01 credits which means you will have 0.01 days worth of hosting. When your hosting credits reach -4 your account will be suspended, they are a little lenient. If you reach -30 hosting credits, all files are deleted and your account is terminated. You can go years without having to post if you can save up a lot of credits. At the moment I have 200 hosting credits so if I wanted I go could go inactive for 200 days and still have my hosting. It's that simple. Refer to the ReadMe in jlhaslip's post for future information regarding credits. That has the answer to just about everything about hosting credits, how to earn them, and what they do.

Thanks Very Much.

But don't you think that rules are pretty strict here!

The rules are actually pretty fair. You're getting FREE webhosting and all they're asking is that you contribute some quality posts to the forums. They even work off a credit system, so you can spend some time making a good, long post on something that you know about or are interested in rather than trying to keep posting on lots of different things. If you write decently enough, you can earn enough credits in a day or two to keep hosted for over a month. They don't require you to "check-in" every few weeks like some of the other post-to-host forums.
If you think that the post requirement is too much for you, you can always try Xisto's quipis service where they add a line of advertising text at the bottom or Computing Host for low cost web hosting. They both have all the same features as Trap17's free services without the posting requirement.