strange problem with subversion merge

Dear list,

Greetings to all of you. Hope you all are well.

I have come back again to discuss on svn merge which is not working at
all here. The version running at server is

````````````
svn, version 1.5.1 (r32289)
compiled Aug 6 2009, 16:55:38
`````````````````

The client pc has

````````````````````````
svn, version 1.6.6 (r40053)
compiled Nov 1 2009, 12:15:31
```````````````````

I have done a checkout of a repo at client and then start making trunk
and branches

[1] svn co https://192.168.1.1/repos/testrepo ./

[2] cd testrepo

svn mkdir trunk branches
svn mv folder1 folder2 folder3 trunk/
svn commit -m "creating trunk and placing files/folder in it"

till now everything is ok

[3] Now making a branch

svn copy trunk branches/mybranch
svn up

all is OK.

[4] and now merging. I have already changed
branches/mybranch/folder1/file1 and commit successfully. "svn diff -r
475:476" reports the changes I made. BUT

````````````````
svn merge -r 475:476 trunk/
`````````````````

just returns null value. It should merge the changes I made at
branches/mybranch/folder1/file1 to trunk/folder1/file1. Have I missed
something ? Please suggest.

thanks

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