Powershell Get-Content to a 2D string array

UPDATED CODE:

I have the following code. I wish to pass the InputTable to the nested script as a 2 dimensional string array, but I can't work out how to get this from the Get-Content (which appears to be a 1D array).

First Script:

$InputTablePath=C:\Temp\test.csv
$InputTable = Get-Content $InputTablePath
$scriptPath = 'C:\Temp\nested_script.csv

$m = Get-Content $tablePath
$rows = $m.count
$cols = ($m[0].split(",")).count

$InputTable = New-Object 'string[,]' $rows,$cols
for ($i=0;$i -lt $rows; $i++){
    for ($j=0;$j -lt $cols; $j++){
        $InputTable[$i,$j]= ($m[$i].split(","))[$j]
   }
}  


$argumentlist = "-InputTable '{0}'" -f $array

Invoke-Expression "& `"$scriptPath`" $argumentList" 

Nested Script:

Param(
    [string[,]]$InputTable
)

$numberOfRows = $InputTable.GetLength(0)
$numberOfColumns = $InputTable.GetLength(1)

etc....

I'm currently getting an index out of bounds error on the last line.

Many Thanks.