diff --git a/lib/brazenhead/builder.rb b/lib/brazenhead/builder.rb
index <HASH>..<HASH> 100644
--- a/lib/brazenhead/builder.rb
+++ b/lib/brazenhead/builder.rb
@@ -10,7 +10,7 @@ module Brazenhead
 
     def build_for(apk)
       @source_apk = apk
-      invalid_package_err unless File.exists? @source_apk
+      invalid_package_err(apk) unless File.exists? @source_apk
       install_server
       manifest_info
     end
@@ -83,8 +83,8 @@ module Brazenhead
       'AndroidManifest.xml'
     end
 
-    def invalid_package_err
-      raise Exception.new("Invalid :package argument")
+    def invalid_package_err(apk)
+      raise Exception.new("Invalid package path:  #{apk}")
     end
 
   end
diff --git a/spec/lib/brazenhead/builder_spec.rb b/spec/lib/brazenhead/builder_spec.rb
index <HASH>..<HASH> 100644
--- a/spec/lib/brazenhead/builder_spec.rb
+++ b/spec/lib/brazenhead/builder_spec.rb
@@ -24,7 +24,7 @@ describe Brazenhead::Builder do
     context "validating the arguments" do
       it "should require that the package exists" do
         File.should_receive(:exists?).and_return(false)
-        lambda { server.build_for('some_package.apk') }.should raise_error
+        lambda { server.build_for('some_package.apk') }.should raise_error(message="Invalid package path:  some_package.apk")
       end
     end
clearer exception when package cannot be found