If you're up for some testing, there are tools I've submitted to Repoforge for building 1.6.18 and 1.7.4 over at http://www.github.com/nkadel/ All the patches and .spec files for building the RPM's, compatble for RHEL 4, 5, and 6. You could rsync the repository to a new environment, build and install the new RPM's there, and see if the error still occurs.
I did have to turn off the "make_check" option for normal RPM compilation, because it takes about an hour to run and it always fails with some of the odder tests for RHEL 4 and RHEL 5. In particular, for RHEL 5 and the subversion-1.7.4 SRPM I've built, building inside a "mock" envronment with the "make check" enabled: : Running all tests in key-test [70/71]...success Running all tests in strings-reps-test [71/71]...success At least one test was SKIPPED, checking /builddir/build/BUILD/subversion-1.6.18/tests.log SKIP: cache-test 2: basic memcache svn_cache test SKIP: cache-test 3: memcache svn_cache with very long keys At least one test XFAILED, checking /builddir/build/BUILD/subversion-1.6.18/tests.log XFAIL: fs-test 18: merging commit XFAIL: locks-test 9: able to reserve a name (lock non-existent path) XFAIL: locks-test 10: directory locks (kinda) XFAIL: tree-conflict-data-test 3: detect broken tree conflict data Summary of test results: 2 tests SKIPPED 4 tests XFAILED make: *** [check] Error 1 error: Bad exit status from /var/tmp/rpm-tmp.67349 (%check)