FileLocator Pro passes the files to the Windows Shell to delete, so it's hard to tell why it's failing. Instead you could try generating a batch file to delete the files using ERASE, e.g.
ERASE "path to file 1"
ERASE "path to file 2"
To generate the batch file you can use the 'Custom (XSLT)' export option with this transform:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:rslt="http://www.mythicsoft.com/FileLocator_16Aug2005"
version="1.0">
<xsl:output method="text" indent="yes"/>
<xsl:template match="/">
<xsl:apply-templates select="//rslt:file"/>
</xsl:template>
<xsl:template match="rslt:file">
<xsl:text>ERASE "</xsl:text>
<xsl:value-of select="rslt:path"/>
<xsl:value-of select="rslt:name"/>
<xsl:text>" </xsl:text>
</xsl:template>
</xsl:stylesheet>