So you were trying to flash a ROM or kernel to your Samsung Galaxy Ace S5830i through ODIN. What was that? Did you say that you (or your cat) accidentally unplugging the device in the middle of the process? While this won't always result in a bricked device, you can likely get stuck in a state where the device is detected by Odin, but nothing can be flashed. For cases like this, XDA Member brijeshep might have the solution.

This convenient tool bundles together everything you need to restore your device, install a stock ROM, or convert a ROM from a flashable zip to an ODIN-compatible format. The bundled tools include the required drivers, ODIN, Cygwin, SplitFus tool, and direct links to stock firmware downloads. The tool itself guides you through the whole process with a convenient and easy-to-use GUI.

You can find the download link and detailed instructions in the forum thread.