You could have a crappy connection with the jumper cables. Been there, done that. Let the battery charge and try again. If it keeps up, you may need a new battery.

If it's been a while since the car ran (as in years), the engine could be tight. If it has been sitting for years, it may be a good idea to pull the spark plugs and spray some fogging oil in each bore and let it sit overnight.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)