我的网页怎么啦，大虾们帮帮忙？？
大虾们帮个忙，
我的一个网页老是出现这样的错误，问题在哪？？
错误类型：
Microsoft VBScript 运行时错误 (0x800A005E)
无效使用 Null: 'replace'
/Default.asp, 第 113 行
网页源码：
if instr(pic,"[img]") then
pic = Replace(pic, "[img]","<img src=")
pic = Replace(pic, "[/img]"," width=160 height=110 border=0>")
else
pic = Replace(pic, "[up]","<img src=upload/") ＜113行＞
pic = Replace(pic, "[/up]"," width=160 height=110 border=0>")
end if
Response.Write (pic)
Response.Write (count)
%>
</A></TD>
</TR>
