Range of Numeric Values that Can Be Entered or Stored in Cells
The maximum numeric value that can be entered (manually) into a cell of Statistica spreadsheets is: ±9.99999E+30 (i.e., ±9.99999..*1030), that is, less than the absolute value of 1E+31.
The purpose of that warning is (a) to protect against typos when entering values in scientific notation (and when entering just a single digit by error, could potentially change a value in a reasonable range into a value of an astronomical magnitude), and (b) to discourage entering unreasonably large values.
Real numbers (Double) are stored in Statistica in a 64-bit IEEE floating point notation with the range of ±1.79769313486231E+308 (i.e., ±1.79769313486231*10308), but this limit pertains to the maximum values that can be internally stored (and which potentially could be a result of multiplying the raw data values, such as squaring them) and, therefore, using extremely large data values as raw input data is not recommended. Such data should be re-scaled after importing them into Statistica, which normally does not involve any loss of information (such as precision).
You can enter data as large as 9.9999..E+30 into a cell (as mentioned above, a warning is displayed if you attempt to enter a larger value), but cells can store much larger values - you can also import much larger values into Statistica or create them in Statistica as a result of transformations (by the spreadsheet formulas or Statistica Visual Basic powerful math library).