Are you using the latest version? And do you have this problem with every SVG file or a only with a specific file?
Edit: After taking a look at the ImageMagick code it seems like it cannot open pixel cache on disk. You might not have write permissions on the temp directory? You can change the temp dir with the following code:
Edit: After taking a look at the ImageMagick code it seems like it cannot open pixel cache on disk. You might not have write permissions on the temp directory? You can change the temp dir with the following code:
MagickNET.SetTempDirectory(@"C:\YourFolder");