You may have already deployed a scheduled task on some clients to be run at the Next Logon (See below the settings concerned for LDMS 9.5 & 9.6).
You hadn't got the time to press on Cancel button in Schedule Tasks menu, when you realised that the package wasn't correct and the tasks are already on Pending/Delayed Status on your Scheduled task in the LDMS Console (See below).
Hence, you'd like to prevent these tasks from launching for each client on Pending Status at the Next Logon.
Step by Step
This is entirely possible by simply delete a registry key value which is created on each client for this the purpose of running the deployment after the Next Logon. These keys are either;
For 32 bits clients; HKLM - SOFTWARE - Intel - LANDesk - LDWM - Distribution - sdclient
For 64 bits clients; HKLM - SOFTWARE - Wow6432Node - Intel - LANDesk - LDWM - Distribution - sdclient
The value of this key value looks like;
/p="\\CORE95SP3.sebdomain.local\ldlogon\Data\NotepadPlusPlus 655 silent.exe" /levels=3 /Hash=KG9YFoFvuv/DrnBUGPy9DQ== /pkgid=1008 /pkgname="NOTEPADPLUSSilent" /FileListName="taskmanifest.CORE95SP3.1016.1008.ini" /FileListHash="fLNBblwNVcgWFawN/oU9xQ==" /exe /N /An /nopeer /nopref /nosource /wan=25 /lan=75 /taskid=1016 /taskName="NOTEPADPLUSSilent - 23/06/2015 02:15:46" /core="CORE95SP3:10.1.1.112" /sad=50 /runfromsource /EnableVirtualAppShortcuts /enableloggedoffuserinstall /dmname="Standard push distribution AFTER LOGIN" /dmtype=3 /E
Then you need to delete these registry key on each client. For that, you may deploy a batch package on the clients concerned and run the following code with the System User;
REG DELETE HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intel\LANDesk\LDWM\Distribution /v sdclient
Then you can also remove these Pending machines from the Scheduled task to make it clean or even delete the scheduled task if you need to.