The jewishgenweb/shtetlseeker is showing a Kronsdorf as being now KRASOV in Czech Republic.
The town is between VRBNO and KRNOV and/or North
Two listings show up in Krnov's phone book for Matzner and Matznerova (female).
The Czech phone book is at http://phone.quick.cz
To find information on the town: http://mesta.obce.cz
Have you checked in the Ellis Island web site for other family members?