Incanto Ant Tasks for ESRI ArcSDE is based on the ArcSDE Java API. Therefore, to use these tasks, the JAR files included within the ArcSDE DevKit needed:
You will not have to install the ArcSDE software on the build machine, you just need these JAR files.
To install the task library, just put the Incanto JAR file and the ArcSDE JAR files (from the ArcSDE DevKit) into Ant's lib directory or classpath.
In your build file declare a namespace (eg "sde") for the Incato task library.
<project ... xmlns:sde="antlib:net.sf.incanto.arcsde">
The Incanto tasks can be used together with that namespace prefix.
<sde:registertable ... >