problem with scketch upload

Using Arduino Programming Questions
#1

core.a(main_orig.cpp.o): In function main': /home/insippo/arduino-0022/hardware/arduino/cores/arduino/main_orig.cpp:7: undefined reference tosetup' /home/insippo/arduino-0022/hardware/arduino/cores/arduino/main_orig.cpp:10: undefined reference to `loop'

ubuntu 10.04, arduino duemilanove and eth shield w5100 with sd card. If i connect eth shield to arduino usb connection filed. if i upload without eth shield : core.a(main_orig.cpp.o): In function main': /home/insippo/arduino-0022/hardware/arduino/cores/arduino/main_orig.cpp:7: undefined reference tosetup' /home/insippo/arduino-0022/hardware/arduino/cores/arduino/main_orig.cpp:10: undefined reference to `loop' again this error what the problem ?

thanks

#2

Does the sketch contain setup() and loop() function definitions? This error suggests the compiler can't find them.

#3

if i connect w5100 shield to arduino, arduino disconnect from usb port and arduino ide says: Error inside Serial.serialEvent() java.io.IOException: Input/output error in nativeavailable at gnu.io.RXTXPort.nativeavailable(Native Method) at gnu.io.RXTXPort$SerialInputStream.available(RXTXPort.java:1532) at processing.app.Serial.serialEvent(Serial.java:215) at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732) at gnu.io.RXTXPort.eventLoop(Native Method) at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575) ubuntu 10.04 and ubuntu 10.10 arduino duemilanove+w5100 with sd card reader

#4