Is it bad practice to append the Environment variable "Path" at run time in your Asp.net MVC project?

I have a web-site in ASP.Net MVC, I have login page to with captcha on it, having a Audio button.

For the Audio functionality it is using the Unmanaged dll to add the background noise in it.

When I run the application and clicking on the Audio but it gave me the exception as below

Unable to load DLL 'libmp3lame.32.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

After searching and googling, I got the solution https://github.com/Corey-M/NAudio.Lame/wiki/Using-NAudio.Lame-with-MVC

Just wana ask, is it the better solution?