i tryed with next code

 Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
    
  ####
  #### Update sharepoint field
  ###
     
 #Get the List, update fields
 $spSite = Get-SPSite -Identity http://test-net.dri.local
 $website = $spSite.OpenWeb()
 $list = $website.Lists["Лична акта"]
 $items = $list.items
    
 foreach($folder in $list.Folders)
 {
     $imeiprezime=$folder["Име и презиме"]
     $korisnickoime=$folder["Корисничко име"]
     $eposta=$folder["Е-пошта"]
     $query = New-Object -Type 'Microsoft.SharePoint.SPQuery'
     $query.Folder = $folder.Folder
     $folderItems = $list.GetItems($query)
     foreach($item in $folderItems)
     {
     if($item["Име и презиме"] -eq "")
         {
             $item["Име и презиме"] = $imeiprezime
               
         }
         if($item["Корисничко име"] -eq "")
         {
             $item["Корисничко име"] = $korisnickoime
              
         }
         if($item["Е-пошта"] -eq "")
         {
             $item["Е-пошта"] = $eposta
                
         }
         $item.Update()
    
     }
 }
 $website.Dispose()

but variable $item cannot update columns. how customize my code

i found where is problem. the variable MinValue is problem. when i set 7800 in code instead MinValue background is yellow. How do i resolve problem with variable MinValue?

i changed code and my template is in file
110929-template-code.txt

now i see the changing in sharepoint designer 2010, but when i open page in web browser again color background is not changed.

ii set breakpoint and i receive file, like a picture below

not, this code give me next message

no, i need web soap service in infopath because of i must filtered infopath form based on group membership.