Complex sentence: However, the ratings had problems, so the channel had to stop airing "Norisuta Hai" on March 31,2007, making "Hamtaro" and "Keroppi" the only anime programs on Nicktoons until June 20,2008.
Split into simpler sentences: However, the ratings had problems, so the channel had to stop airing "Norisuta Hai" on March 31,2007. Making "Hamtaro" and "Keroppi" the only anime programs on Nicktoons until around June 20,2008.