Special behaviour by reading SD card in context with LPD8806 stripe

Hi, on my Arduino Uno I read data from an SD card to run a LPD8806 stripe. Everything works fine so far.
On the SD card there are stored some light-choreos in separate files.
I have tested all of them seperatly and they’re running fine.

But unfortunately if I put them in different orders (see below) they’re running in example 1 and 2.
In example 3 I got an error message: “error opening PUNK6~1.TXT”

Why is this?

Leo

Example 1 (works fine)

      case 0: // lesen von SD-Card
          if(mbUmschalt){
              mbUmschalt = false;
              Serial.println("case 0 - lesen von SD-Card");
          }                
          /*
          SD_Card_read("BEECRO~1.TXT"); 
          SD_Card_read("WILLIA~1.TXT");
          SD_Card_read("WWW_AK~1.TXT"); 
          SD_Card_read("_WHITE~1.TXT"); 
          */
          SD_Card_read("PUNK6~1.TXT");      
          break;          
          // (...)

Example 2 (works fine)

      case 0: // lesen von SD-Card
          if(mbUmschalt){
              mbUmschalt = false;
              Serial.println("case 0 - lesen von SD-Card");
          }                
          
          SD_Card_read("BEECRO~1.TXT"); 
          SD_Card_read("WILLIA~1.TXT");
          SD_Card_read("WWW_AK~1.TXT"); 
          SD_Card_read("_WHITE~1.TXT"); 
          
          /* SD_Card_read("PUNK6~1.TXT");  */
          break; 
          // (...)

Example 3 (shows error)

      case 0: // lesen von SD-Card
          if(mbUmschalt){
              mbUmschalt = false;
              Serial.println("case 0 - lesen von SD-Card");
          }                
          
          SD_Card_read("BEECRO~1.TXT"); 
          SD_Card_read("WILLIA~1.TXT");
          SD_Card_read("WWW_AK~1.TXT"); 
          SD_Card_read("_WHITE~1.TXT");
          
          SD_Card_read("PUNK6~1.TXT"); 
          break; 
          // (...)
void SD_Card_read(String sDatei)
{
    // open the file. note that only one file can be open at a time,
    // so you have to close this one before opening another.
      
    dataFile = SD.open(sDatei);
    if (dataFile) { // if the file is available, write to it:
        Serial.println("File '" + sDatei + "' exists.");
        while (dataFile.available()) {      
            
            for( int i = 0; i < NUM_LEDS; i++) {
                leds[i] = CRGB(0, 0, 0); // set to black
            }
            for( int i = 0; i < NUM_LEDS; i++) {          
                leds[i] = CRGB(dataFile.read(), dataFile.read(), dataFile.read());
            }
            FastLED.show();
            FastLED.delay(1000 / UPDATES_PER_SECOND);        
        }
        dataFile.close();    
    }else{ // if the file isn't open, pop up an error:
        Serial.println("error opening " + sDatei);
    }
}

Keep your filename 8.3 ?