for asp.net, there are 2 spaces to set the maximun upload size.
1. in web.config, like this
<httpRuntime executionTimeout="6000" maxRequestLength="150000" />
2. in IIS=>Request Filtering:
if your upload file is exceed the max lengh, you will get error like
404 - File or directory not found.
The resource you are looking for might have been removed, had its name changed, or is temporarily unavailable.
