Regarding to {FileExists()} variable
You should use only file name as parameter, like this:
{FileExists(C:\temp\file.tmp)}
or variable which contains single file name
{FileExists({MyFile})}
you can't use the list of filenames. If you have the list you should process it in the text loop
Regarding to your task:
I think that you don't need to uese {FileExists()} variable. See the example below:
;*****************************
;* RoboTask Task file
;* Do not edit in text editor!
;*****************************
[Root]
ActionAfterRun=INTEGER|0
Actions=FOLDER
Automat=INTEGER|-1
CatID=INTEGER|1005538731
Comment=STRINGLIST
ContinueOnError=INTEGER|0
ExternalName=STRING|"Task1081"
Hide=INTEGER|0
ID=INTEGER|1670688694
LocalVariables=STRING|"filelist"
LogOnAsUser=INTEGER|1
Name=STRING|"Send files in folder"
OnErrorTaskID=INTEGER|0
Priority=INTEGER|3
RunOnClose=INTEGER|0
RunOnStartup=INTEGER|0
ToLog=INTEGER|3
WriteGeneralLog=INTEGER|0
[Actions]
Action1=FOLDER
Action2=FOLDER
Action3=FOLDER
Action4=FOLDER
Action5=FOLDER
Action6=FOLDER
Action7=FOLDER
[Actions\Action1]
ActionID=STRING|"A_FILE_DELETE"
Enabled=INTEGER|-1
Name=STRING|"Delete File"
Params=FOLDER
[Actions\Action1\Params]
Count=STRING|"1"
deletedirs=STRING|"0"
file0=STRING|"c:\temp\list.txt"
hidden=STRING|"1"
subdir=STRING|"0"
system=STRING|"1"
ToRecycleBin=STRING|"0"
[Actions\Action2]
ActionID=STRING|"A_FILE_SEARCH"
Enabled=INTEGER|-1
Name=STRING|"Create File List (c:\temp\list.txt)"
Params=FOLDER
[Actions\Action2\Params]
After=STRING|"0"
aftercount=STRING|"0"
AfterLine=STRING|"0"
Before=STRING|"0"
beforecount=STRING|"0"
BeforeLine=STRING|"0"
createmode=STRING|"1"
date1=STRING|"20110725"
date2=STRING|"20110725"
destfile=STRING|"c:\temp\list.txt"
DuringDays=STRING|"1"
DuringHours=STRING|"1"
DuringMinutes=STRING|"1"
DuringMonths=STRING|"1"
file0=STRING|"c:\incoming\*.abc"
filecount=STRING|"1"
OlderDays=STRING|"1"
OlderHours=STRING|"1"
OlderMinutes=STRING|"1"
OlderMonths=STRING|"1"
searchkind=STRING|"0"
subdirs=STRING|"1"
WithoutPath=STRING|"0"
[Actions\Action3]
ActionID=STRING|"A_FLOW_IF"
Enabled=INTEGER|-1
Name=STRING|"If Then"
Params=FOLDER
[Actions\Action3\Params]
case=STRING|"0"
operator=STRING|"7"
type=STRING|"0"
value1=STRING|"{TextFile(c:\temp\list.txt)}"
[Actions\Action4]
ActionID=STRING|"A_DIALOG_MESSAGE"
Enabled=INTEGER|-1
Name=STRING|"Show ""File list is empty!!!!"""
Params=FOLDER
[Actions\Action4\Params]
icon=STRING|"1"
msg0=STRING|"File list is empty!!!!"
msgcount=STRING|"1"
playsound=STRING|"0"
showmessage=STRING|"1"
[Actions\Action5]
ActionID=STRING|"A_FLOW_ELSE"
Enabled=INTEGER|-1
Name=STRING|"Else"
[Actions\Action6]
ActionID=STRING|"A_INET_SENDMAIL"
Enabled=INTEGER|-1
Name=STRING|"Send Email"
Params=FOLDER
[Actions\Action6\Params]
attach0=STRING|"{TextFile(c:\temp\list.txt)}"
attachcount=STRING|"1"
auth=STRING|"0"
charset=STRING|"iso-8859-1"
from=STRING|"
user@domain.com"
host=STRING|"localhost"
html=STRING|"0"
msg0=STRING|"See files in attachment"
msgcount=STRING|"1"
port=STRING|"25"
SSL=STRING|"0"
subject=STRING|"Files"
to=STRING|"
user1@domain.com"
[Actions\Action7]
ActionID=STRING|"A_FLOW_ENDIF"
Enabled=INTEGER|-1
Name=STRING|"End If"