为什么我的jspSmartUpload不能上传图片？大家帮忙看看

我使用jspSmartUpload来上传图片到服务器上。
在本地可以，windows系统，可是同样的程序在服务器上就不可以执行，服务器是linux系统。
这是上传的语句：
newName = "/pic/" + cmdid + "."+ myFile.getFileExt();
myFile.saveAs(newName, SmartUpload.SAVE_VIRTUAL);错误信息：
exception org.apache.jasper.JasperException: File can't be saved (1120).
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:476)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:371)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)
root cause javax.servlet.ServletException: File can't be saved (1120).
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:846)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:779)
org.apache.jsp.admin.cmdtymge.newcmdtyinst_jsp._jspService(newcmdtyinst_jsp.java:196)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)
root cause com.jspsmart.upload.SmartUploadException: File can't be saved (1120).
com.jspsmart.upload.File.saveAs(File.java:108)
org.apache.jsp.admin.cmdtymge.newcmdtyinst_jsp._jspService(newcmdtyinst_jsp.java:143)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:328)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:315)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:121)