svn: A working copy merge source needs an explicit revision

Can someone explain to me what this means? In english.

Here's the problem. This message came up today and I don't know why nor how to fix it.

In the past I've had trunk checked out to /path/to/trunk
and my branch checked out to /path/to/myBranch

and I was able to do a merge from my branch to trunk simply by being in that path and doing the command like so

/path/to/trunk > svn merge --dry-run /path/to/myBranch .

After which I could go over the merge resolve conflicts etc then commit.

But now I get this message and I don't know why. Please, someone, anyone help.
Received on 2011-01-25 23:30:00 CET