Vous devez concaténer le '%'
littéraux :
AND APP_FRAMES.APP_EXT_CODE LIKE '%' || :IN_APP_EXT_CODE || '%';
La requête entière serait :
QUERY_STR := 'select * from APP_FRAME_PROPERTIES,APP_FRAMES
Where APP_FRAME_PROPERTIES.APP_EXT_CODE = APP_FRAMES.APP_EXT_CODE
AND APP_FRAMES.APP_EXT_CODE LIKE ''%'' || :IN_APP_EXT_CODE || ''%'' ';