Hello and welcome to 4images forum.
What is the path to convert.exe do you use?
Some people reported that they had to use double back slashes: C:\\ImageMagick\\convert.exe
other reported that they had to install IM into a folder, so there was no spaces in the path (i.e. C:/Program Files/ImageMagic/convert.exe didn't work)
If changing path didn't help, try
[MOD] Batch Copy/Move/Edit Images, it might reveal more details about the error.