Can reproduce it in Drawing and Impress with DEV300m37 on WinXP and Ubuntu

How to reproduce it
1 Create a Drawing (or Impress, it's up to you) document
2 Insert - Table, 'Insert Table' dialog appears, 
  Number of columns: 6
  Number of rows: 5
  Click 'OK' button to insert a 6*5 table
3 Select cells in the cross of second row, first column and second column,
  click 'Merge cells' on Table bar, See attached image: First-MergeCells.png
4 Select cells in the cross of third row, first column and second column,
  click 'Merge cells' on Table bar, See attached image: Second-MergeCells.png
5 Select cells in the cross of second row,third row, first column and second column,
  click 'Merge cells' on Table bar, See attached image: Third-MergeCells.png
6 Select the cell that you just do merging cells at step5, then click 'Split Cells',
  See attached image: Split-Third-MergeCells.png
7 Set cursor to the cell containing 'Third' Content, then click 'Merge Cells'

Result
OOo crashes

Expectation
OOo works well