Nios II IDE HelloWorld Build error

Hello,

Everytime I try to build Hello World project, I obtain the following error:

Kind Status Priority Description Resource In Folder Location

Error *** [C:/altera/Design/software/hello_world_0_syslib/Debug/system_description/../obj/generated_app.mk-t] Error 1 hello_world_0

I am using Nios II Development Kit 1.1.

Any idea??????????

Thanks in advance,

Jasmine