This comes hard to admit, but I feel quite strongly that this prefix should be changed along with the prefix "Ver-." Both were inspired by German verb prefixes that are identical, but mean entirely different things. In German, "ge-" makes past participles. This makes things very needlessly confusing for any German who might attempt to learn Dovahzul.
Apart from the conflicts with German, those prefixes don't fit the dragon language all that well. "E" is rarely used, and "Er" especially is very atypical of canon.
I have a few suggestions for alternatives to "Ge-": Mo-/No-, So-, Ti-, Tu-. Feel free to make any others. I could be a suffix, too.