diff -Nru sks-1.1.3/debian/changelog sks-1.1.3/debian/changelog
--- sks-1.1.3/debian/changelog	2012-07-06 20:31:54.000000000 +0000
+++ sks-1.1.3/debian/changelog	2012-10-04 17:44:34.000000000 +0000
@@ -1,3 +1,10 @@
+sks (1.1.3-1ubuntu3) quantal; urgency=low
+
+  * debian/sks.postinst: LP: #1061769
+    - detect if Ubuntu system, even if dpkg-vendor is not available
+
+ -- Dustin Kirkland <kirkland@ubuntu.com>  Thu, 04 Oct 2012 12:44:23 -0500
+
 sks (1.1.3-1ubuntu2) quantal; urgency=low
 
   * Look for ^.i not ^ii in libdbX.Y-dev packages for BDB_VERSION. And assert
diff -Nru sks-1.1.3/debian/sks.postinst sks-1.1.3/debian/sks.postinst
--- sks-1.1.3/debian/sks.postinst	2012-07-02 11:19:39.000000000 +0000
+++ sks-1.1.3/debian/sks.postinst	2012-10-04 17:46:25.000000000 +0000
@@ -73,7 +73,8 @@
 	if [ -r /var/lib/sks/berkeley_db.active ]; then
 	    OLD_BDB=$(cat /var/lib/sks/berkeley_db.active)
 	else
-	    if dpkg-vendor --derives-from Ubuntu; then
+	    if (type dpkg-vendor >/dev/null && dpkg-vendor --derives-from Ubuntu) || \
+			[ -e /etc/dpkg/origins/ubuntu ]; then
 		if dpkg --compare-versions "$2" lt "1.1.1+dpkgv3-6.1"; then
 		    OLD_BDB=4.7
 		else