You don’t say much in the way of what error you are experiencing but yes, those characters are supported. The small letter t with caron, small letter n with caron, small letter l with caron, capital letter D with caron, and small letter c with acute are x’DD’, x’8B’, x’57’, x’FA’, and x’49’ respectively in CCSID 870. I would make sure in addition to the terminal using 870 that the job CCSID and the source physical file are also using CCSID 870.
As one indication of the level of support, you can order your system for Slovakian with feature code 2994. You can see the characters supported in CCSID 870 by going here and displaying code page 870.
I hope this helps,