Keil C编译问题 ，一直出错会的帮忙解决下

Question

Build target 'Target 1'
compiling exam3_1.c...
linking...
BL51 BANKED LINKER/LOCATER V6.22 - SN: Eval Version
COPYRIGHT KEIL ELEKTRONIK GmbH 1987 - 2009
"STARTUP.obj",
"exam3_1.obj"
TO "exam3.1"
RAMSIZE(256)
*** FATAL ERROR L211: I/O ERROR ON OUTPUT FILE:
EXCEPTION 0029H: ACCESS TO FILE DENIED
FILE: exam3.1
Target not created

以上是错误信息

其实我的代码很简单，如下：
#include
void main()
{
while(1)
P1=0x00;
}

求解！

Answer 1

EXCEPTION 0029H: ACCESS TO FILE DENIED
输出目录是否存在，程序是否权限足够。win7上以管理员权限运行Keil C