If dns server option is returned without a domain option, pump will core dump, since it doesn't check for a null domain in createResolveConf(). I would suggest skipping over existing search records in resolv.conf if the domain isn't present to at least preserve what is there.
There is a patch that fixes this and other problems in pump (as well as reporting errors in syslog) at http://www.cse.ucsc.edu/~breed/pump.patch.
This was fixed a while ago, and the version on the errata should already include the fix.