Dear Sirs and Madams!

I am working on some Android app I and I have begun with Splash Screen. I've presented SplashScreen as Activity and two extra xml files: layout_activity_splashscreen.xml (in res/layout subdir) and style_activity_splashscreen.xml (in res/style subdir, which was created by me using New Folder command). Now, if I try to build a project, I get following error:
"clean:
Deleting directory C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\bin
Deleting directory C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\gen
Gathering info for demo_splashscreen...
Android SDK Tools Revision 16
Project Target: Android 4.0.3
API level: 15
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Resolving library dependencies:
No library dependencies.

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WARNING: No minSdkVersion value set. Application will install on all Android versions.
Creating output directories if needed...
Created dir: C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\bin
Created dir: C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\bin\res
Created dir: C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\gen
Created dir: C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\bin\classes
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Handling aidl files...
No AIDL files to compile.
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Handling RenderScript files...
No RenderScript files to compile.
----------
Handling Resources...
Generating resource IDs...
invalid resource directory name: C:\Users\markofr\Documents\Projects\Android\demo_s plashscreen\res/style
C:\Program Files (x86)\Android\android-sdk\tools\ant\build.xml:560: The following error occurred while executing this line:
C:\Program Files (x86)\Android\android-sdk\tools\ant\build.xml:589: null returned: 1
BUILD FAILED (total time: 0 seconds)
Why am I getting this error and how do I get rid of it?

Sincerely,
Marko