Guys, i find a solution for the Error Go to this link and download the zip file.after that, open the file and drag the RAGENativeUI.dll to the game directory. Than launch the game.Its worked for me.
The Beta started on December 10th, 2015, and received its first public update on December 23rd. A second public update was released on March 1st, 2016 with a hotfix on March 10th, 2016. On May 3rd, another public update incorporated Steam Workshop support, allowing players to upload and download new levels through Steam.
The developers left the old alpha version of the editor in the retail version of HLM2 and it can be accessed via exploits. A modded .exe containing the alpha build must be downloaded, and put it in the game directory. (Works for both Steam and GOG edition) 2b1af7f3a8