"backup" behavior and corrupted file

[droki]

Hi,

I'm having trouble running "tahoe backup" involving two different
issues. First, my backup command keeps getting stuck on a single file.
It just hangs on the file.

In fact, this behavior isn't limited to "backup", when I run "tahoe
check URI:CHK:..." on the URI in question I get the same result - it
just hangs.

This brings me to my second issue. I was trying to work around this
problem and thought "I'll just make a whole new backup."  So I ran
"tahoe backup" and specified a new directory as the destination. But I
saw that tahoe was still skipping all the files that had previously been
backed up, so it wasn't creating  a new complete backup. Is this the
intended behavior?

And, even when specifying a new destination, the backup command got
stuck on the same URI.

How can I create a totally new backup?  What should I think of this bad URI?

Thanks.

-droki