receive error getting marc record while using wonderfetch

After clicking 'LOAD' in wonderfetch, the following error message displays in biblio while trying to get the marc record:
Getting MARC record ...

YAZ::getYazRecord() ERROR! invalid YAZ resource

BiblioYaz Object
(
    [class:protected] => YAZ
    [context:protected] => YAZ::getYazRecord()
    [arcUrl:protected] => http://www.archive.org
    [usUrl:protected] => http://www.us.archive.org
    [reqArgs] => Array
        (
            [b_id] =>
            [b_v] =>
            [b_c2] => navalpostgraduateschoollibrary;fedlink;americana
            [b_c3] => z0316
            [b_sf] =>
            [b_l] => Naval Postgraduate School, Dudley Knox Library
            [b_p] => Naval Postgraduate School, Dudley Knox Library
            [b_n] => sanfrancisco
            [z_c] => local
            [z_d] => ocn640324967
            [z_e] => Naval Postgraduate School, Dudley Knox Library
            [rights] => Approved for public release, distribution unlimited
            [w_creator] => Beckwith, Reynolds
            [w_subject] => Electronics
            [w_publisher] => Monterey, California: U.S. Naval Postgraduate School
            [w_date] => 1956
            [w_language] => en_US
            [w_wonderfetch] => 1
            [w_title] => A mechanical transducer for low frequency sonic cleaning.
            [b_o] => JesseBell
        )

    [itemId] =>
    [itemUrl] =>
    [itemLink] =>
    [itemHost] =>
    [itemDir] =>
    [itemXmlUrl] =>
    [itemXml] =>
    [metaXmlUrl] =>
    [metaXml] =>
    [zCatalog] => Naval Postgraduate School, Dudley Knox Library
    [zField] => local
    [zTerm] => ocn640324967
    [zResource] => bosun.nps.edu:2200/unicorn
    [zFieldmap] => naval
    [zTarget] => Array
        (
            [handle] => nps
            [title] => Naval Postgraduate School, Dudley Knox Library
            [identifier] => bosun.nps.edu:2200/unicorn
            [syntax] => USMARC
            [charset] => marc-8
            [elementset] => F
            [fieldmap] => naval
            [display] => marc
        )

    [zAttributes] => Array
        (
            [term] => 1=1016
            [title] => 1=4
            [author] => 1=1003
            [subject] => 1=21
            [isbn] => 1=7
            [standard] => 1=8
            [local] => 12=1
            [date] => 1=1016 s=al 4=2 3=3
            [call] => 1=16
        )

    [zParams] =>
    [yaz] =>
    [zquery] => local=ocn640324967
    [cclquery] => @attr 12=1 ocn640324967
    [yazHits] =>
    [yazRecNo] => 1
    [yazRecType] => xml; charset=marc-8,ISO-8859-1
    [marc] =>
    [marcXml] =>
    [marcBin] =>
    [dcXml] =>
    [sourceXml] =>
    [mtype:protected] => t
    [stype:protected] => u
    [forced_record_mod:protected] =>
    [CLI] => 0
    [yazNext] => 1
    [yazPrev] => 2
)

This happens with multiple items.