title: Assertion failed Invalid spriteFrameName
body: <p>I am building a game using <code>Cocos2dx</code>. I have a sprite sheet and animation plist that specifies where all the images are.</p>
  
  <p>For some reason when loading my game I get the following error:</p>
  
  <pre><code>(char [256]) msg = "Invalid spriteFrameName: PlayButton.png"
  </code></pre>
  
  <p>It is coming from line 159 of <code>CCSprite.cpp</code>:</p>
  
  <pre><code>CCSprite* CCSprite::createWithSpriteFrameName(const char *pszSpriteFrameName)
  {
      CCSpriteFrame *pFrame = CCSpriteFrameCache::sharedSpriteFrameCache()-&gt;spriteFrameByName(pszSpriteFrameName);
  
  #if COCOS2D_DEBUG &gt; 0
      char msg[256] = {0};
      sprintf(msg, "Invalid spriteFrameName: %s", pszSpriteFrameName);
      CCAssert(pFrame != NULL, msg);
  #endif
  
      return createWithSpriteFrame(pFrame);
  }
  </code></pre>
  
  <p>I checked in my .plist and I do have an entry for PlayButton.png, so I have no idea why it says it is invalid.</p>
  
  <p>That method is being called from the <code>MainMenu::init()</code> method:</p>
  
  <pre><code>fileName = (CCString*)sc-&gt;imageDict-&gt;objectForKey("GUI_StartButton-image");
  CCSprite *startGameSprite = CCSprite::createWithSpriteFrameName( fileName-&gt;m_sString.c_str() ); &lt;--- CRASHING HERE
  </code></pre>
  
  <p><strong>What could be causing this?</strong></p>