Help running tenshi no inai 12-gatsu/天使のいない12月

i was able to install the game but when i run it i get popup saying to insert the disc. the autorun exe doesn't do anything either

there was a note that was included with the download that said to rename the exe patch (tenshi_cd.exe) to tenshi_dvd.exe and then run it but that didn't work.
the note didn't say to but i moved the patch into the folder where i installed the game and then tried to run it but i get a popup saying the DL couldn't be found.