Data import stuck at "Uploading Import file..."

Data import stuck at "Uploading Import file..."

I have uploaded one file this morning with no problem. However, now I am trying to upload a second set of leads.  The file in Excel97, with only 1000 records.  After browsing to find the target file, I click next. At this point, the process goes to "Uploading Import file..." with a progress bar that does not advance.
 
I receive the same results in IE and Firefox.
 
Although I am running the free edition, the notes say I am limited to 1500 records per batch. I assume a batch as being a single import, so I am assuming that is not the problem. I have also checked for any quotes.
 
Any other suggestions?