The term <function-name> is not recognized as the name of a cmdlet, function, ...

This is my code. I'm trying to unzip files, edit them, and zip them back. For some reason functions DeGZip-File and GZip-File are not being recognized. Could anyone point out what could be wrong here?

Function DeGZip-File {
[CmdletBinding()]
param($infile)

$infile
$outfile = ($infile -replace '\.gz$','')
try
{
$input = New-Object System.IO.FileStream $inFile, ([IO.FileMode]::Open), ([IO.FileAccess]::Read), ([IO.FileShare]::Read)
$output = New-Object System.IO.FileStream $outFile, ([IO.FileMode]::Create), ([IO.FileAccess]::Write), ([IO.FileShare]::None)
$gzipStream = New-Object System.IO.Compression.GzipStream $input, ([IO.Compression.CompressionMode]::Decompress)

$buffer = New-Object byte[](1024)
while($true){
$read = $gzipstream.Read($buffer, 0, 1024)
if ($read -le 0){break}
$output.Write($buffer, 0, $read)
}
return $outfile
}
catch
{
Write-Host "$_.Exception.Message" -ForegroundColor Red
}
finally
{
$gzipStream.Close()
$output.Close()
$input.Close()
}
}

#Zip them back after adding the headers
Function Gzip-File {
[CmdletBinding()]
param($outfile)

$srcFile = Get-Item -Path $outfile
$newFileName = "$($srcFile.FullName).gz"

try
{
$srcFileStream = New-Object System.IO.FileStream($srcFile.FullName,([IO.FileMode]::Open),([IO.FileAccess]::Read),([IO.FileShare]::Read))
$dstFileStream = New-Object System.IO.FileStream($newFileName,([IO.FileMode]::Create),([IO.FileAccess]::Write),([IO.FileShare]::None))
$gzip = New-Object System.IO.Compression.GZipStream($dstFileStream,[System.IO.Compression.CompressionMode]::Compress)
$srcFileStream.CopyTo($gzip)
}
catch
{
Write-Host "$_.Exception.Message" -ForegroundColor Red
}
finally
{
$gzip.Dispose()
$srcFileStream.Dispose()
$dstFileStream.Dispose()

}
}

$headerProcess = {
#param($file,$headerArray)

$file = $folder + "\" + $file
$unZippedFile = DeGZip-File($file)
$unZippedFile[1]

$unZippedFile = $unZippedFile[1]
$filedata = import-csv $unZippedFile -Header $headerArray
$filedata | export-csv $unZippedFile -NoTypeInformation

GZip-File $unZippedFile
}

function Add-Headers([string]$folder, [string]$schemaFilePath){

if($schemaFilePath -eq 'TallOptionsSchema.txt')
{

$tallOptionsSchema = Get-Content $schemaFilePath
$strArray = [string[]]$tallOptionsSchema
$headerArray = $strArray -join "`t"
}
else
{

$JSONFromFile = Get-Content -Raw -Path $schemaFilePath | ConvertFrom-Json
$header = $JSONFromFile.schema.name

$strArray = [string[]]$header
$headerArray = $strArray -join "`t"
}

$filesToModify = Get-ChildItem $folder -Recurse -File

foreach ($file in $filesToModify)
{
Start-Job -Name $file.Name -ScriptBlock $headerProcess -ArgumentList ($file,$headerArray)
}

}

$folderPath = 'D:\Working\options'
$schemafile = 'D:\Working\options\schema.json'
Add-Headers $folderPath $schemafile

Get-Job

# Wait for it all to complete
While (Get-Job -State "Running")
{
Start-Sleep 10
}

# Getting the information back from the jobs
Get-Job | Receive-Job
Get-Job | remove-job -Force