Error -200802 occurred at DAQmx Write (Analog Wfm 1Chan NSamp).vi:6
Measurements: Write cannot be performed when the task is not started, the auto start input to DAQmx Write is false, the Sample Timing Type is something other than On Demand, and the output buffer size is zero.
Call DAQmx Start before DAQmx Write, set auto start to true, modify the Sample Timing Type, or change the output buffer size.
Error -201025 occurred at DAQmx Write (Analog Wfm 1Chan NSamp).vi:6
Measurements: Non-buffered hardware-timed operations are not supported for this device and Channel Type.
Set the Buffer Size to greater than 0, do not configure Sample Clock timing, or set Sample Timing Type to On Demand.
Could you repost with your VI attached? Since you are using DAQmx Write (Analog Wfm 1Chan NSamp), I assume you are generating a continuous analog output. The errors you posted are common when you do not preload the buffer. The general sequence is as follows:
4. Write more
I would suggest taking a look at one of the shipping examples found in the NI Example Finder. Open up LabVIEW and go to Help»Find Examples. Browse to Hardware Input and Output»DAQmx»Analog Generation. A good one to look at is Cont Gen Voltage Wfm-Int Clk.vi.