Today I made a page for XSP to upload a file using <input type="file" ....> and I had problems with big files. The problem was in the maximum length allowed for the requests of the HttpRuntime (used by XSP). This value is by default 4096 in mono 1.1.8 but it can be changed in the file "machine.config". I found that settings in Configuration/System.Web/HttpRuntime path.