File modification check template contains two monitors returning file age in seconds (relative to current time), for local system (VBScript) and for remote system available via SSH (Shell).
Download and unpack the template archive (look for download link below)
Move the file-modification-age.vbs file from archive into C:\Scripts folder
Load the "File modification check.xml" template (via "Tools > Templates > Import Template" in IPHost GUI client), and apply monitor(s) as required
Replace (in arguments) first monitor argument (in "Main parameters") to the path of the file you need to check the age of
IF you prefer to keep .vbs scripts elsewhere, change the path to the script in VBScript monitor correspondingly. Note that the script should be accessible by the account IPHost monitoring service runs under (typically, it is SYSTEM).