Is there anything in your machine's event logs that might have a bit more detail?
Are you using one of our samples?
If not, would it be possible to post a bit of your code?
When you are trying to perform the file transfer, are you logged in as an administrator or standard user?
What version of XFile are you using?
You can find the version of XFile from several places:
1. In IE, under Tools > Manage Add-ons. From the drop-down select "All add-ons." You should see SoftArtisans XFile under the list of add-ons. If you select the add-on, in the details area should be the version (e.g. 220.127.116.1104).
2. On the file transfer page, in the source should be the <object> tag under the "codebase" attribute. The number will be seperated by commas instead of periods (e.g. "2,5,1,1222").