Could not add X to the ignore list?

[Sod Almighty]

Why, when telling TortoiseSVN to ignore a specific file, do I get this error message?

There seems to be no rhyme or reason, and no way to determine the actual cause of the message. Some files can be ignored, others throw this error.

What is going on?

[Sod Almighty]

It has been over a year. Nobody is going to respond to this?

[Daniel Sahlberg]

If you give more details maybe it will be easier to give productive feedback.

* What version of TSVN are you using?

* What is the value the svn:ignore property?

* What are the exact steps you take when you try to add the file? Do you add from the 

On a quick test I'm unable to reproduce, and without reproduction it is difficult to narrow down the reason.