an typo error vs a typo error

Some examples from the web:

• It's obvious there is a typo error.
• There must be a typo error, because everyone's talking about the power of thinking big online.
• Some of the typo errors occur because the spellchecker will not make any distinction among genuine words thus it fails to check the syntax.
• Please ensure that you submit accurate data into the on-line application system at the time of seeking ESTA approval and avoid typo errors.
• Most writers (translators are writers as well) believe that it is best to know the typo errors they constantly commit.
• No, you're not seeing things, it's not a typo error, I did say 300VA.
• And speaking of writing, it cannot be helped that there will be some typo errors, grammatical errors and other writing errors that can happen.
• This includes, and is not limited to, any words containing, or derived from, the names of the Sites or the brands used on them, and any typo errors or phonetics of them.
• Place a note in the text next to a printer's erorr[*typo for error?].
• I've also noted down typos and grammar errors.
• Even the best writers are prone to typos or other errors.
• I found a few typos and grammatical errors, so I retyped it.
• But even if your email is well-formatted and has no typos or grammatical errors, it's not enough.
• Think of every typo and error as a lost customer.Show the high level of attention to detail that your business values.It's always best to get someone else to take a look at your work, especially if you're not very confident with your editing skills.
• Electronic data collection virtually eliminates typos and errors, as well as problems with writing legibility, loss of writing utensils and the effects of weather on paperwork.
• It also helps me locate any wayward typos or grammar errors, even ones that I missed on my first four or five rounds of editing.
• Create a Professional Image From Day One.Make sure that your work is as close to perfect as you can make it: DEFINITELY no typos or grammatical errors.
• To save time, I saw they used the same sequence, which is ok... but they could have fixed the typos and spelling errors if they had thoroughly checked the campaigns before and after each webinar.
• Members agree that the data contained in the invoice correspond exactly to what is stated in the catalog of sale, except to correct any typos or errors in the catalog.
• It can help ensure your document is perfectly presented without spelling errors or typos. If a word you type is not entered in your bilingual dictionary, InteractiveTran will sound an alarm and display a list of suggested spellings.

Some examples from the web:

• It's obvious there is a typo error.
• There must be a typo error, because everyone's talking about the power of thinking big online.
• No, you're not seeing things, it's not a typo error, I did say 300VA.
• I found a few typos and grammatical errors, so I retyped it.
• Some of the typo errors occur because the spellchecker will not make any distinction among genuine words thus it fails to check the syntax.
• Please ensure that you submit accurate data into the on-line application system at the time of seeking ESTA approval and avoid typo errors.
• Most writers (translators are writers as well) believe that it is best to know the typo errors they constantly commit.
• And speaking of writing, it cannot be helped that there will be some typo errors, grammatical errors and other writing errors that can happen.
• This includes, and is not limited to, any words containing, or derived from, the names of the Sites or the brands used on them, and any typo errors or phonetics of them.
• Place a note in the text next to a printer's erorr[*typo for error?].
• I've also noted down typos and grammar errors.
• Even the best writers are prone to typos or other errors.
• But even if your email is well-formatted and has no typos or grammatical errors, it's not enough.
• Think of every typo and error as a lost customer.Show the high level of attention to detail that your business values.It's always best to get someone else to take a look at your work, especially if you're not very confident with your editing skills.
• Electronic data collection virtually eliminates typos and errors, as well as problems with writing legibility, loss of writing utensils and the effects of weather on paperwork.
• It also helps me locate any wayward typos or grammar errors, even ones that I missed on my first four or five rounds of editing.
• Create a Professional Image From Day One.Make sure that your work is as close to perfect as you can make it: DEFINITELY no typos or grammatical errors.
• To save time, I saw they used the same sequence, which is ok... but they could have fixed the typos and spelling errors if they had thoroughly checked the campaigns before and after each webinar.
• Members agree that the data contained in the invoice correspond exactly to what is stated in the catalog of sale, except to correct any typos or errors in the catalog.
• It can help ensure your document is perfectly presented without spelling errors or typos. If a word you type is not entered in your bilingual dictionary, InteractiveTran will sound an alarm and display a list of suggested spellings.