my map file is reversed from your example, but that is so that it works with my other rules.
# Helicon ISAPI_Rewrite configuration file
# Version 3.0.0.29
RewriteLog "C:\Program Files\Helicon\ISAPI_Rewrite3\newrewrite.log"
ErrorLog "C:\Program Files\Helicon\ISAPI_Rewrite3\newerror.log"
RewriteLogLevel 9
LogLevel debug
RewriteEngine on
RewriteBase /
RewriteMap zips txt:mapfiles/zipmap.txt
RewriteMap cats txt:mapfiles/catmap.txt
RewriteMap subcats txt:mapfiles/subcatmap.txt
RewriteMap headers txt:mapfiles/headermap.txt
RewriteMap clients txt:mapfiles/clientmap.txt
#search1 rule
RewriteRule ^search1/([^/]+).html search1.aspx?zip=${zips:$1} [NC,L]
#search2 rule
RewriteRule ^search2/([^/]+)/([^/]+).html search2.aspx?zip=${zips:$2}&subcategoryid=${subcats:$1} [NC,L]
#search3 rule
RewriteRule ^search3/([^/]+)/([^/]+).html search3.aspx?zip=${zips:$2}&header=${headers:$1} [NC,L]
#the below rule will be used for the dynamic client page
RewriteRule ^companies/([^/]+)/([^/]+)/([^/]+).html companies/website.aspx?client_id=${clients:$1}&zip=${zips:$2}&header=${headers:$3} [NC,L]
#These rules are for alod link style redirects
#RewriteCond %{QUERY_STRING} ^zip=(\d+)$ [NC]
#RewriteRule ^search1\.aspx$ search1/%1.html? [NC,R=301,L]
#
#RewriteCond %{QUERY_STRING} ^zip=(\d+)&subcat=(\d+)$ [NC]
#RewriteRule ^search2\.aspx$ search2/%1/%2.html? [NC,R=301,L]
#
#RewriteCond %{QUERY_STRING} ^zip=(\d+)&heading=(\d+)$ [NC]
#RewriteRule ^search3\.aspx$ search3/%1/%2/%3.html? [NC,R=301,L]
RewriteRule ^search1-zip-([^/]+)\.html search1/${zips:$1}.html [NC,R=301]
#RewriteRule ^search1-zip-([^/]+)\.html search1.aspx?zip=${zips:$1} [NC,R=301]
Log File
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] init rewrite engine with requested uri /search1/19380.html
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] Htaccess process request C:\Program Files\Helicon\ISAPI_Rewrite3\httpd.conf
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] Htaccess process request C:\Inetpub\new.bythezip.com\.htaccess
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] applying pattern '^search1/([^/]+).html' to uri 'search1/19380.html'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] escaping /search1.aspx?zip=
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] Rewrite URL to >> /search1.aspx?zip=
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] rewrite 'search1/19380.html' -> '/search1.aspx?zip='
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] init rewrite engine with requested uri /index.aspx
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] Htaccess process request C:\Program Files\Helicon\ISAPI_Rewrite3\httpd.conf
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] Htaccess process request C:\Inetpub\new.bythezip.com\.htaccess
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search1/([^/]+).html' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search2/([^/]+)/([^/]+).html' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search3/([^/]+)/([^/]+).html' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^companies/([^/]+)/([^/]+)/([^/]+).html' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search1\.aspx$' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search2\.aspx$' to uri 'index.aspx'
Mon, 12-May-2008 15:40:52 GMT [btz.dyndns.biz/sid#864830077][rid#19734760] applying pattern '^search3\.aspx$' to uri 'index.aspx'
Mon, 12-May-2008 15:42:04 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] init rewrite engine with requested uri /search1-Zip-19508.html
Mon, 12-May-2008 15:42:04 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] Htaccess process request C:\Program Files\Helicon\ISAPI_Rewrite3\httpd.conf
Mon, 12-May-2008 15:42:04 GMT [btz.dyndns.biz/sid#864830077][rid#19734464] Htaccess process request C:\Inetpub\new.bythezip.com\.htaccess