When communicating in Chinese you may often make mistakes using Chinese grammar like:

False:

    请告诉小李来我那儿。

    Qǐng gàosù Xiǎo Lǐ lái wǒ nà’ér 

True:

    请告诉小李来我这儿。

    Qǐng gàosù Xiǎo Lǐ lái wǒ zhè‘ér .

远指和近指的混淆。“小李”的行为动作“来”是朝着说话人（“我”）进行的，距离说话人很近。应当用“这儿”。

The error lies in the confusion of two words of close and distant reference respectively. 那儿 refers to a location further away from the speaker while 这儿 refers to somewhere around the speaker. The action 来 which is towards the speaker（我）brings 小李 close to 我. Thus 这儿 is the right word.