Trying to upload document to a document library from custom aspx page

Hi,

Created custom aspx page with custom fields and one browse button to attach document and submit button to submit values and attachment to a document library.

My solution adds attached document to document library along with metadata when user clicks submit button.

My solution is working fine some times but some times it is not updating one lookup field in library and the issue is when I am trying to open up the document in browser in word, I am getting below error.

"The file cannot be opened because there are problems with the contents. The file is corrupt and cannot be opened."

Can anybody help me out to resolve the issue?

Any help would be appreciated.

Thank you.

AA.