Error reading XLSX

Hi,

I'm trying to read in an XSLX using the XLSDataReader and am having some issues.
I've narrowed down the issue to 3 adjacent columns in my file and if I map any of these three columns in the reader component, I get an error message:

ERROR [WatchDog] - Node XLS_GROUPS finished with status: ERROR caused by: Cannot get a text value from a error cell
ERROR [WatchDog] - Node XLS_GROUPS error details:
java.lang.IllegalStateException: Cannot get a text value from a error cell
	at org.apache.poi.xssf.usermodel.XSSFCell.typeMismatch(XSSFCell.java:845)
	at org.apache.poi.xssf.usermodel.XSSFCell.getRichStringCellValue(XSSFCell.java:294)
	at org.apache.poi.xssf.usermodel.XSSFCell.getStringCellValue(XSSFCell.java:246)
	at org.jetel.data.parser.XLSXDataParser.parseNext(XLSXDataParser.java:487)
	at org.jetel.data.parser.XLSParser.getNext(XLSParser.java:132)
	at org.jetel.util.MultiFileReader.getNext(MultiFileReader.java:415)
	at org.jetel.component.XLSReader.execute(XLSReader.java:606)
	at org.jetel.graph.Node.run(Node.java:414)
	at java.lang.Thread.run(Thread.java:619)
WARN  [exNode_0_1306204897681_TRASH0] - TRASH0thread interrupted, it will interrupt child threads
java.lang.InterruptedException
	at java.lang.Object.wait(Native Method)
	at java.lang.Thread.join(Thread.java:1151)
	at org.jetel.component.Trash.executeWithoutWriter(Trash.java:278)
	at org.jetel.component.Trash.execute(Trash.java:241)
	at org.jetel.graph.Node.run(Node.java:414)
	at java.lang.Thread.run(Thread.java:619)
ERROR [TRASH0_0.InputThread#0] - 34: thread forcibly aborted
java.lang.InterruptedException
	at java.lang.Object.wait(Native Method)
	at java.lang.Object.wait(Object.java:485)
	at org.jetel.graph.DirectEdge.fillReadBuffer(DirectEdge.java:216)
	at org.jetel.graph.DirectEdge.readRecordDirect(DirectEdge.java:182)
	at org.jetel.graph.Edge.readRecordDirect(Edge.java:363)
	at org.jetel.component.Trash$InputReader.run(Trash.java:471)

I have no idea what an "error cell" is but it's a simple text column in the spreadsheet.

Any thoughts?

Thanks in advance!
Chris