What you mean by "m guessing it's because it's somehow not properly finding autocad..."?, if you are trying to use that code in AutoCAD, you should first netload the dll, if you are trying that code from an external exe, it wont work as managed code *need* to be netloaded in AutoCAD.
Reason: The Autodesk installer defaults its AutoCAD verticals into the same vanilla AutoCAD folder located at C:\Program Files\Autodesk\AutoCAD 2013. If there is already an existing AutoCAD 2013 installed and updated with additional hotfixes or service packs, subsequent vertical installations of AutoCAD 2013 from other suites will fail.
Recommended Installation: If you plan to install more than one AutoCAD 2013 from different suites onto the same computer (i.e. AutoCAD 2013, Building Design Suite, Product Design Suite, etc.) it is recommended to install the products sequentially and without adding any service packs or hotfixes during the installation nor immediately after installation.
By default, if there is a valid Internet connection and there is an available service pack available for the product, the Autodesk installer will include it during installation. To avoid this, you must expand the AutoCAD 2013 (or vertical) installation options and choose the radio button labeled Do not include Service Pack(s).
Repeat this process for every AutoCAD 2013 Suite that you plan on installing, ensuring that you do not install any Service Pack for any AutoCAD 2013 installation during, nor immediately after installation. For detailed instructions on how to install your Autodesk products, you can refer to the videos listed in this Autodesk Knowledge Base article:
Once installation is completed for all products, you should be able to individually launch each version of AutoCAD 2013 from its respective Suite. After you have verified installation and licensing, then you can install the appropriate service pack(s) to your AutoCAD 2013.
Note: Installing the Service Pack for one supported AutoCAD 2013 Suite will also subsequently install it for all AutoCAD 2013 products installed into that folder. Please see the Readme for the Service Pack that you are installing to ensure that all of your products are up-to-date.
Additional Information: If you already have AutoCAD 2013 or vertical installed and updated with hotfixes or service packs, then you will need to do the following to install additional Suites:
I am installing almost the complete Education Master Suite 2013 on many different computers(some imaging but also different computer models). If I do my installations this way, it will be time consuming to do all my installs, then update each of the softwares one by one. Once done, start on the next one.... Is there a fix on the way for this or are we up the creek without a paddle?
I am having problems installing Design Suite Premium 2013. I initially installed Design Suite on clean computer and it installed fine. Then I trired to install Autocad Architecture 2013 and it would not allow me. I read isssues regarding suites and stand alone installations so I uninstalled suite. I then installed Autocad Architecture 2013, everything fine. I also installed Autodesk Civil 3D 2013, everything fine. Now try to install Design Suite again, and installation fails.