OpenEuphoria

[...] I wonder if spawnvp() simply can't deal with spaces in its arguments but requires them to be quoted. (IMNSHO it shouldn't, but this is windoze after all.) So that suggests another thing to try is this:

string="\"C:\\Windows\\System32\\notepad.exe\""&" "&"\"\\\"C:\\Program Files (x86)\\EuDesigner\\license.txt\\\"\"" 
system_exec(string) 
puts(1,string&"\n") 
any_key()