encoding problems

Hi I am very confusing with these encoding systems.  UTF-8 and iso-8859-1. Some of the characters are ok with one of the encoding systems but not all and vice versa.

For example this statement is OK with UTF-8  and UTF-16 encoding system  not withthe iso-8859-1 :
"hola mujeres quién anda ahi"

The following is OK with is0-8859-1 but not with UTF-8 and as well UTF-16
"¤H*OL*Ƥ Peluchotes como estan espero q super preciosas me encantaria conocer amigas caleñitas"

The following is the exception which I am getting on, i dont know how far the can helps you.. But it alwasy says like this "illegal utf8 encoding at 0xf1". I coudn't get this 0xf1, what exactly does this and what does this means ??

exception [stream:155: illegal utf8 encoding at 0xf1
dk.realtime.duckling.framework.JSPServiceServletException: stream:155: illegal utf8 encoding at 0xf1
        at dk.realtime.duckling.framework.JSPResponse.show(JSPResponse.java:591)
        at dk.realtime.service.chatdate.chat.one2many.services.ChatJSPServiceServlet.doService(ChatJSPServiceServlet.java:87)
        at dk.realtime.duckling.framework.JSPServiceServlet.service(JSPServiceServlet.java:154)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
        at com.caucho.server.http.FilterChainServlet.doFilter(FilterChainServlet.java:96)
        at dk.realtime.duckling.backend.wapbilling.web.SubscribeFilter.forwardToContent(SubscribeFilter.java:120)
        at dk.realtime.duckling.backend.wapbilling.web.SubscribeFilter.doFilter(SubscribeFilter.java:96)
        at com.caucho.server.http.FilterChainFilter.doFilter(FilterChainFilter.java:88)
        at com.caucho.server.http.Invocation.service(Invocation.java:315)
        at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
        at com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
        at com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
        at com.caucho.server.TcpConnection.run(TcpConnection.java:139)
        at java.lang.Thread.run(Thread.java:534)
Caused by: dk.realtime.duckling.framework.JSPServiceServletException: stream:155: illegal utf8 encoding at 0xf1
        at dk.realtime.duckling.framework.JSPResponse.show(JSPResponse.java:581)
        ... 13 more
Caused by: java.io.CharConversionException: stream:155: illegal utf8 encoding at 0xf1
        at com.caucho.xml.readers.Utf8Reader.error(Utf8Reader.java:175)


Thanks a lot for your help.

Upender Gilakathula