Help with strange merge issues on feature branch

Hi guys,
  I'm having some really strange issues with merging in SVN 1.6 that
I've never had before. We're performing a big migration from Lucene to
Solr. We correspondingly have the following repository.

services/trunk
service/branches/solr

I'm working on the solr branch, and 3 other engineers are working on
trunk. Every evening I merge their bug fixes into my branch with the
following command.

working copy remote url: https://svn.foobar.com/services/branches/solr

svn merge https://svn.foobar.com/services/trunk

Everything merges, and I don't have any issues in the branches/solr
branch. Now I'm trying to merge from my branch back to trunk, and it's
a nightmare.

working copy remote url:https://svn.foobar.com/services/trunk

svn merge https://svn.foobar.com/services/branches/solr

This ignores all the changes I've made in the solr branch. I was able
to get the merge to work, but only with --ignore-ancestry. It was a
merge nightmare, especially since no changes to trunk have occurred
since my last merge into the solr branch.

I initially tried this command for the solr-> trunk merge.

svn merge https://svn.foobar.com/services/branches/solr --reintegrate

but I receive this error.

svn: Reintegrate can only be used if revisions 725 through 782 were
previously merged from
https://staff.spidertracks.com/svn/aviator/application/services/trunk to
the reintegrate source, but this is not the case:
  application/services/branches/solr
    Missing ranges: /application/services/trunk:725-737

Not sure what's going on, as I said I've merged nightly with out issue,
and the merge from trunk to the solr branch results in a no-op, so I
know I'm up to date.

Any ideas what's going wrong and how I can solve it?

Thanks,

-- 
todd