most likely, the database connection string in your web.config file (in the root of your IIS website) does not point to a valid SQL server and database. In DNN 4, you needed to enter proper connection string (maybe even twice - I am not sure for DNN 4), please check out the comments (should be around line 20 usually).

Thank you so much dear Sebastian, I have replaced the installation folder with a clean one of the equal version and everything is working fine right now.
But I have faced other problems.
Could you please let me how I could install modules from desktop modules folder? I dont have access to the source modules that had been installed on the original project .

you can install modules from packages (.Zip files) only, based on the .dnn file inside.
if you need to reinstall a module, check folder \app_data\ExtensionPackages, which should contain copies of the packages.

Are you trying to install modules that are installed on another DNN installation? If so, you may be able to edit those modules in the other site and "Create Module." This will create zip files that you can use to install in the new installation.

You may run into some issues here regarding the Manifest files that get created. If you have an option to use existing manifest files, try that option first.

Please note that any module data in the old site will not be transferred. First you need to install the modules and then you need to move the data. This could be a fairly big project if the modules do not support import and export.

 

You will be much better off if you can make a copy of the existing site and move it to your other environment.  Most likely, that can save you days of work.

Thank you for your response, actually I am about to fix some issues regarding the project. I have just copied the entire folder of installed dnn and referenced from iis. Please consider that I am really new to the dotnetnuke and all .net environment. As of now, I am responsible to fix some problems in written modules but as I said I have no access to the packages source files.
Also there is no package folder in app data folder. But I have another question. If i change something in the module codes doest it apply to the project or i need to reinstall the whole module? for example consider that there is a piece of code generating a string with length 20 character and inserts it to the database with an exact char size, if i change the size of generated string to 30 chars and also alter the size of regarding field in the database to the same size, would it work properly? or i have to do something else?

Bests

Don't forget that you also need to get a copy of the database installed on your development environment, create a website, give a local portal alias to your DNN portal(s), adjust the connection string(s) in web.config, and set permissions for the web directory to give control to the IIS worker process. You also need to make sure that the IIS worker task can connect to the database.

I'd suggest creating an install of the same version of DNN to your development entironment using nvQuick site so that you can see how all of the wiring is done.

In terms of the modules, this all depends on whether or not you are using compiled modules. If the modules don't install compiled libraries, you should be able to edit the ascx, vb, and cs files to your liking. But, if that's the case, and for lots of good reasons, you should convert all of that to compiled modules. Chris Hammond's templates for DNN modules will give you a good start on that.

But, before you do any of that sort of thing you should start upgrading the installation, at least in development) to the current version of DNN. That's DNN 9.10.1. Do that first, and get past all of the hurdles. You'll likely learn a a bit about DNN in the process, and your upgraded DNN will be very much for secure and perform better than what you have. DNN 4 is so old that it makes the dinosaurs seem young!

As for upgrades, you'll probably be able to 8.0.4 fairly quickly. Follow the upgrade path shown at https://dnndocs.com/conte...ade-path/index.html. Since you are at 4.4.0, first upgrade to 4.4.1 and then use the upgrade path.

I think that the biggest problem you will encounter on the way to 8.0.4 is possible skin and container issues. When you hit them, they are easy to fix and we can guide you through the process.

And, the first thing that you need to learn is how to make a backup (database and file directory)> Make a backup at every step. So, if something goes wrong, you can restore the previous good version and try again.

Another approach is to hire someone to help you through the process. Things should go quicker and you'll probably learn more.

Good luck!