A poster has asked questions about a .25 ACP Erma on the WTB Board where they can't be answered... but here are some of my somewhat opinionated answers:
To look for parts or whole guns, the correct nomenclature is Erma-Werke EP25 (oder wenn sie Deutsch sprechen, Erma-Werke EP25 Taschen-Pistole). They have pot-metal (zinc) frames and since by federal law their frame is the firearm and yours is broken, you really have a something useless that can't be fixed and wouldn't be much good if it were fixed... essentially nothing at all, except it might get someone in trouble anyway if they carried it around in their pocket (even in unfirable condition) without a license. Back in the days those were made, in the '60s and '70s, used ones went for about 20 bucks "on the street". They were an archetypical "Saturday Night Special", and since their striker firing design dates back to the '30s they are probably dangerous to carry with a round chambered. The only thing any good about them is that they are sort of a concealable gun, and one that if it works when the trigger is pulled someone might shoot someone with from a maximum range of 4 or 5 feet and if that was done they could probably die from it eventually, but not anytime soon enough to do you much good if the other person had a knife, piece of iron pipe, chain, broken bottle, hammer... whatever... maybe a ball point pen to shove up your nose.
I'm amazed to see them talked about on the web as being worth $100 or more in really good shape, though $20 in the '60s had the buying power of $100 or more now... but because so many so much incredibly better guns are available now. I would suggest throwing that broken thing in the trash and buying something worth the money, even if it costs several times more money than a working EP25. The EP25 is a junk gun, even if not broken.
But if you are a totally driven, hell-bent glutton for punishment: http://www.gun-parts.com/erma/