Pass as separate params, not 1.

build-installer.xml

     <target name="-installer-build-stable" if="has.bash">
         <exec executable="/bin/bash" dir="installer" resultproperty="installer.result">
             <arg value="release.sh"/>
-            <arg value="-c -t"/>
+            <arg value="-t"/>
+            <arg value="-c"/>
         </exec>
 
         <condition property="installer.success">
     <target name="-installer-build-unstable" if="has.bash">
         <exec executable="/bin/bash" dir="installer" resultproperty="installer.result">
             <arg value="release.sh"/>
-            <arg value="-c UNSTABLE -t"/>
+            <arg value="-t"/>
+            <arg value="-c"/>
+            <arg value="UNSTABLE"/>
         </exec>
 
         <condition property="installer.success">