In my opinion, the Eraser tool isn't worth using. Besides the fact that it often doesn't work (for me and also many other messages like this) it's more of a paint or raster tool that is wedged into a vector program. For what functionality it contains, I honestly find little to no use for it in my day to day use of Inkscape.
For a vector program like Inkscape, I choose to use vector tools, such as editing or deleting paths or nodes. Or maybe some path operations (booleans).
Can you tell us the specific part of your drawing that you want to erase? Then we can teach you how to handle it in a vector way
