diff --git a/src/Composer/DependencyResolver/Solver.php b/src/Composer/DependencyResolver/Solver.php
index 567df0273..c5c35acec 100644
--- a/src/Composer/DependencyResolver/Solver.php
+++ b/src/Composer/DependencyResolver/Solver.php
@@ -937,7 +937,11 @@ class Solver
             $this->installedMap[$package->getId()] = $package;
         }
 
-        $this->decisionMap = new \SplFixedArray($this->pool->getMaxId() + 1);
+        if (version_compare(PHP_VERSION, '5.3.2', '>')) {
+            $this->decisionMap = new \SplFixedArray($this->pool->getMaxId() + 1);
+        } else {
+            $this->decisionMap = array_fill(0, $this->pool->getMaxId() + 1, 0);
+        }
 
         foreach ($this->jobs as $job) {
             switch ($job['cmd']) {