Error using "G-code keyboard"

[Jeroen1278]

Hi there,

first of all great project.

But i have a problem.
I am using a arduino mega, ramps 1.4 board and a nextion 4,3 screen.
Almost everything is working fine.
Except when i use the "G-code" keyboard.
I can type the command and send it but when i look in my serial monitor i get a "error":

Echo:enqueueing "e: "
Echo:Unknown command: "e: "

And nothing happens on the machine.
Other commands like homing are working fine.
Below the output of the serial monitor from my arduino IDE.

Does anybody knows a solution for this.
Thanks a lot.

////////////////////////////////////////////////////////////////////////////////////////////////////////
start
Info:Echo:MK4duo_4.3.5
Echo:Last Updated: Apr 2 2018 10:31:45 | Author: (Jeroen van den Berg)
Echo:Compiled: Apr 2 2018
Echo:Free Memory: 531 PlannerBufferBytes: 1248
Error:SD init fail
Echo:EEPROM version mismatch (EEPROM=?? MK4duo=MKV45)
Echo:Hardcoded Default Settings Loaded
Config: G21 ; Units in mm
Config:Steps per unit:
Config: M92 X160.000 Y160.000 Z3200.000 T0 E185.000
Config:Maximum feedrates (units/s):
Config: M203 X500.000 Y500.000 Z40.000 T0 E25.000
Config:Maximum Acceleration (units/s2):
Config: M201 X2000 Y2000 Z30 T0 E1000
Config:Acceleration (units/s2): P<print_accel> V<travel_accel> T* R<retract_accel>
Config: M204 P2000.000 V2000.000 T0 R2000.000
Config:Advanced variables: S<min_feedrate> V<min_travel_feedrate> B<min_segment_time_us> X<max_xy_jerk> Z<max_z_jerk> T* E<max_e_jerk>
Config: M205 S0.000 V0.000 B20000 X10.000 Y10.000 Z0.400 T0 E5.000
Config:Hotend Sensor parameters: H P A B C R L O
Config: M305 H0 P13 A100000.0 B4092.0 C0.0000000000 R4700.0 L0 O0
Config:Hotend Heater parameters: H P A B C L O U<Use Pid 0-1> I<Hardware Inverted 0-1>
Config: M306 H0 P10 A40 B230 C255 L5 O275 U1 I0
Config:Bed Sensor parameters: P A B C R L O
Config: M305 H-1 P14 A100000.0 B4092.0 C0.0000000000 R4700.0 L0 O0
Config:Bed Heater parameters: P A B C L O U<Use Pid 0-1> I<Hardware Inverted 0-1>
Config: M306 H-1 P8 A80 B255 C255 L5 O150 U0 I0
Config:PID settings:
Config: M301 H0 P40.00 I7.00 D60.00
Config:Fans: P U L F H I<Hardware Inverted 0-1>
Config: M106 P0 U9 L1 F250 I0
Config:Auto Bed Leveling:
Config: M420 S0
Config:Probe Offset:
Config: M851 X30.000 Y0.000 Z-1.600
Stats: Total: 0, Finished: 0, Failed: 0
Stats: Total print time: 0s, Power on time: 0s
Stats: Filament used: 0Km 0m 0cm 0mm
Nextion 4.3" connected!
Error:SD init fail
wait
Error:SD init fail
wait
wait
////////////// typing command " G28 " and this is what i am getting back ///////////////////
Echo:enqueueing "e: "
Echo:Unknown command: "e: "
//////////////////////////////////////////////////////
wait
wait
wait