Citing "development reasons", Capcom Japan has chosen to postpone the release of Rockman Zero Collection, changing the April 22 release date to an undetermined, "TBA" date, according to a message at the game's official website:
Capcom apologizes for the inconvenience and will update the game's official site with a new release date as soon as a decision is made. No word if the delay will affect the English version (June 2010), but depressing news nonetheless. I'll keep you informed.
[Capcom JPN Support]