If when using Windows Sharepoint Services you are unable to retract or execute jobs seen through the management interface using the following commands can help to manually list and remove and redeploy solutions.

To see a list of all solutions on the server
stsadm.exe -o enumsolutions To see a list of all deployments
stsadm.exe -o enumdployments To cancel a deployment
stsadm.exe -o canceldeployment -id {guid} To execute scheduled jobs
stsadm.exe -o execadmsvcjobs

Error: "the solution cannot be removed when a job is scheduled or is running" < use the above commands to execute jobs that are scheduled

I am using something like the following when removing and deploying web parts (notice the execadmsvcjobs)

stsadm.exe -o retractsolution -name webPart.wsp -immediate -url {http://...}  stsadm.exe -o execadmsvcjobs
stsadm.exe -o deletesolution -name webPart.wsp -override
stsadm.exe -o addsolution -filename webPart.wsp
stsadm.exe -o deploysolution -name webPart.wsp -immediate -allowgacdeployment -url {http://...} -force
stsadm.exe -o execadmsvcjobs